Stories about how people somehow know when they are being watched have been going around for centuries. However, few (1)________ have been made to study the phenomenon scientifically. Now, with the accomplishment of the largest ever research of the so-called staring effect, there is striking indication that this is a recognizable and (2)________ sixth sense. The research elaborates thousands of kids. For the research, they stood with their eyes covered and with their backs to other youngsters, who were told to either stare at them or look away. The outcomes constantly revealed that the kids who could not see were able to (3)________ when they were being stared at. In total of 14.000 experiments (4)________ globally, the teenagers (5)________ sensed when they were being watched almost 81% of the time.

Điền vào số 1

Stories about how people somehow know when they are being watched have been going around for centuries. However, few (1)________ have been made to study the phenomenon scientifically. Now, with the accomplishment of the largest ever research of the so-called staring effect, there is striking indication that this is a recognizable and (2)________ sixth sense. The research elaborates thousands of kids. For the research, they stood with their eyes covered and with their backs to other youngsters, who were told to either stare at them or look away. The outcomes constantly revealed that the kids who could not see were able to (3)________ when they were being stared at. In total of 14.000 experiments (4)________ globally, the teenagers (5)________ sensed when they were being watched almost 81% of the time.

Điền vào số 2

Stories about how people somehow know when they are being watched have been going around for centuries. However, few (1)________ have been made to study the phenomenon scientifically. Now, with the accomplishment of the largest ever research of the so-called staring effect, there is striking indication that this is a recognizable and (2)________ sixth sense. The research elaborates thousands of kids. For the research, they stood with their eyes covered and with their backs to other youngsters, who were told to either stare at them or look away. The outcomes constantly revealed that the kids who could not see were able to (3)________ when they were being stared at. In total of 14.000 experiments (4)________ globally, the teenagers (5)________ sensed when they were being watched almost 81% of the time.

Điền vào số 3

Stories about how people somehow know when they are being watched have been going around for centuries. However, few (1)________ have been made to study the phenomenon scientifically. Now, with the accomplishment of the largest ever research of the so-called staring effect, there is striking indication that this is a recognizable and (2)________ sixth sense. The research elaborates thousands of kids. For the research, they stood with their eyes covered and with their backs to other youngsters, who were told to either stare at them or look away. The outcomes constantly revealed that the kids who could not see were able to (3)________ when they were being stared at. In total of 14.000 experiments (4)________ globally, the teenagers (5)________ sensed when they were being watched almost 81% of the time.

Điền vào số 4

Stories about how people somehow know when they are being watched have been going around for centuries. However, few (1)________ have been made to study the phenomenon scientifically. Now, with the accomplishment of the largest ever research of the so-called staring effect, there is striking indication that this is a recognizable and (2)________ sixth sense. The research elaborates thousands of kids. For the research, they stood with their eyes covered and with their backs to other youngsters, who were told to either stare at them or look away. The outcomes constantly revealed that the kids who could not see were able to (3)________ when they were being stared at. In total of 14.000 experiments (4)________ globally, the teenagers (5)________ sensed when they were being watched almost 81% of the time.

Điền vào số 5

The volume of traffic in many cities in the world today continues to expand. This (1)________ many problems, including serious air pollution, lengthy delays, and the greater risk (2) ________ accidents. Clearly, something must be done, but it is often difficult to persuade people to change their habits and leave their cars at home.

          One possible approach is to make it more expensive for people to use their cars be increasing changes for parking and bringing in tougher fines for anyone who (3) ________ the law. In addition, drivers could be required to pay for using particular routes at different times of the day. This system, also known as ‘road pricing’, is already being introduced in a number of cities, using a special electronic card (4) ________ to windscreen of the car.

          Another ways of dealing with the problem is to provide cheap parking on the outskirts of the city, and strictly control the number of vehicles allowed into the centre. Drivers and their passengers then use a special bus service for the final stage of their journey.

          Of course, the most important (5) ________ is to provide good public transport. However, to get people to give up the comfort their cars, public transport must be felt to be reliable, convenient and comfortable, with fares charged at an acceptable level.

Điền vào số 1

The volume of traffic in many cities in the world today continues to expand. This (1)________ many problems, including serious air pollution, lengthy delays, and the greater risk (2) ________ accidents. Clearly, something must be done, but it is often difficult to persuade people to change their habits and leave their cars at home.

          One possible approach is to make it more expensive for people to use their cars be increasing changes for parking and bringing in tougher fines for anyone who (3) ________ the law. In addition, drivers could be required to pay for using particular routes at different times of the day. This system, also known as ‘road pricing’, is already being introduced in a number of cities, using a special electronic card (4) ________ to windscreen of the car.

          Another ways of dealing with the problem is to provide cheap parking on the outskirts of the city, and strictly control the number of vehicles allowed into the centre. Drivers and their passengers then use a special bus service for the final stage of their journey.

         Of course, the most important (5) ________ is to provide good public transport. However, to get people to give up the comfort their cars, public transport must be felt to be reliable, convenient and comfortable, with fares charged at an acceptable level.

Điền vào số 2

The volume of traffic in many cities in the world today continues to expand. This (1)________ many problems, including serious air pollution, lengthy delays, and the greater risk (2) ________ accidents. Clearly, something must be done, but it is often difficult to persuade people to change their habits and leave their cars at home.

          One possible approach is to make it more expensive for people to use their cars be increasing changes for parking and bringing in tougher fines for anyone who (3) ________ the law. In addition, drivers could be required to pay for using particular routes at different times of the day. This system, also known as ‘road pricing’, is already being introduced in a number of cities, using a special electronic card (4) ________ to windscreen of the car.

          Another ways of dealing with the problem is to provide cheap parking on the outskirts of the city, and strictly control the number of vehicles allowed into the centre. Drivers and their passengers then use a special bus service for the final stage of their journey.

        Of course, the most important (5) ________ is to provide good public transport. However, to get people to give up the comfort their cars, public transport must be felt to be reliable, convenient and comfortable, with fares charged at an acceptable level.

Điền vào số 3

The volume of traffic in many cities in the world today continues to expand. This (1)________ many problems, including serious air pollution, lengthy delays, and the greater risk (2) ________ accidents. Clearly, something must be done, but it is often difficult to persuade people to change their habits and leave their cars at home.

          One possible approach is to make it more expensive for people to use their cars be increasing changes for parking and bringing in tougher fines for anyone who (3) ________ the law. In addition, drivers could be required to pay for using particular routes at different times of the day. This system, also known as ‘road pricing’, is already being introduced in a number of cities, using a special electronic card (4) ________ to windscreen of the car.

          Another ways of dealing with the problem is to provide cheap parking on the outskirts of the city, and strictly control the number of vehicles allowed into the centre. Drivers and their passengers then use a special bus service for the final stage of their journey.

         Of course, the most important (5) ________ is to provide good public transport. However, to get people to give up the comfort their cars, public transport must be felt to be reliable, convenient and comfortable, with fares charged at an acceptable level.

Điền vào số 4

The volume of traffic in many cities in the world today continues to expand. This (1)________ many problems, including serious air pollution, lengthy delays, and the greater risk (2) ________ accidents. Clearly, something must be done, but it is often difficult to persuade people to change their habits and leave their cars at home.

          One possible approach is to make it more expensive for people to use their cars be increasing changes for parking and bringing in tougher fines for anyone who (3) ________ the law. In addition, drivers could be required to pay for using particular routes at different times of the day. This system, also known as ‘road pricing’, is already being introduced in a number of cities, using a special electronic card (4) ________ to windscreen of the car.

          Another ways of dealing with the problem is to provide cheap parking on the outskirts of the city, and strictly control the number of vehicles allowed into the centre. Drivers and their passengers then use a special bus service for the final stage of their journey.

          Of course, the most important (5) ________ is to provide good public transport. However, to get people to give up the comfort their cars, public transport must be felt to be reliable, convenient and comfortable, with fares charged at an acceptable level.

Điền vào số 5

Last year thieves broke into a Scottish stately home and stole only one thing: a rhino horn trophy, which at 1.5 meters was the longest in the world. Meanwhile, in China, pharmaceutical factories have been building up (1)___________ of antiques made from rhino horn, for the sole purpose of smashing them to powder to make the (2)___________ ingredient of many of their medicines. And in Zimbabwe, 34 poachers died in 1990 in the search for the black rhino.

Recently, conservationists met to (3)___________a campaign to persuade countries where rhino horn is still part of the traditional medicine to switch to substitutes. The biggest threat to the survival of the rhinoceros is the refusal of certain countries to enforce a ban on domestic trading in rhino horn.

The rhino horn is included in many doses for disorders raging from fevers to nosebleeds. Horn, like fingernails, is made of keratin and has no proven medicinal (4)___________. Traditional substitutes, such as horn from buffalo or antelope, are regarded as second best.

The battle is thought to be winnable. But it may be harder than the battle against the trade in ivory, for there is a (5)___________between the two commodities. Ivory is a luxury; rhino horn, people believe, could save the life of their child.

Điền vào số 1

Last year thieves broke into a Scottish stately home and stole only one thing: a rhino horn trophy, which at 1.5 meters was the longest in the world. Meanwhile, in China, pharmaceutical factories have been building up (1)___________ of antiques made from rhino horn, for the sole purpose of smashing them to powder to make the (2)___________ ingredient of many of their medicines. And in Zimbabwe, 34 poachers died in 1990 in the search for the black rhino.

Recently, conservationists met to (3)___________a campaign to persuade countries where rhino horn is still part of the traditional medicine to switch to substitutes. The biggest threat to the survival of the rhinoceros is the refusal of certain countries to enforce a ban on domestic trading in rhino horn.

The rhino horn is included in many doses for disorders raging from fevers to nosebleeds. Horn, like fingernails, is made of keratin and has no proven medicinal (4)___________. Traditional substitutes, such as horn from buffalo or antelope, are regarded as second best.

The battle is thought to be winnable. But it may be harder than the battle against the trade in ivory, for there is a (5)___________between the two commodities. Ivory is a luxury; rhino horn, people believe, could save the life of their child.

Điền vào số 2

Last year thieves broke into a Scottish stately home and stole only one thing: a rhino horn trophy, which at 1.5 meters was the longest in the world. Meanwhile, in China, pharmaceutical factories have been building up (1)___________ of antiques made from rhino horn, for the sole purpose of smashing them to powder to make the (2)___________ ingredient of many of their medicines. And in Zimbabwe, 34 poachers died in 1990 in the search for the black rhino.

Recently, conservationists met to (3)___________a campaign to persuade countries where rhino horn is still part of the traditional medicine to switch to substitutes. The biggest threat to the survival of the rhinoceros is the refusal of certain countries to enforce a ban on domestic trading in rhino horn.

The rhino horn is included in many doses for disorders raging from fevers to nosebleeds. Horn, like fingernails, is made of keratin and has no proven medicinal (4)___________. Traditional substitutes, such as horn from buffalo or antelope, are regarded as second best.

The battle is thought to be winnable. But it may be harder than the battle against the trade in ivory, for there is a (5)___________between the two commodities. Ivory is a luxury; rhino horn, people believe, could save the life of their child.

Điền vào số 3

Last year thieves broke into a Scottish stately home and stole only one thing: a rhino horn trophy, which at 1.5 meters was the longest in the world. Meanwhile, in China, pharmaceutical factories have been building up (1)___________ of antiques made from rhino horn, for the sole purpose of smashing them to powder to make the (2)___________ ingredient of many of their medicines. And in Zimbabwe, 34 poachers died in 1990 in the search for the black rhino.

Recently, conservationists met to (3)___________a campaign to persuade countries where rhino horn is still part of the traditional medicine to switch to substitutes. The biggest threat to the survival of the rhinoceros is the refusal of certain countries to enforce a ban on domestic trading in rhino horn.

The rhino horn is included in many doses for disorders raging from fevers to nosebleeds. Horn, like fingernails, is made of keratin and has no proven medicinal (4)___________. Traditional substitutes, such as horn from buffalo or antelope, are regarded as second best.

The battle is thought to be winnable. But it may be harder than the battle against the trade in ivory, for there is a (5)___________between the two commodities. Ivory is a luxury; rhino horn, people believe, could save the life of their child.

Điền vào số 4

Last year thieves broke into a Scottish stately home and stole only one thing: a rhino horn trophy, which at 1.5 meters was the longest in the world. Meanwhile, in China, pharmaceutical factories have been building up (1)___________ of antiques made from rhino horn, for the sole purpose of smashing them to powder to make the (2)___________ ingredient of many of their medicines. And in Zimbabwe, 34 poachers died in 1990 in the search for the black rhino.

Recently, conservationists met to (3)___________a campaign to persuade countries where rhino horn is still part of the traditional medicine to switch to substitutes. The biggest threat to the survival of the rhinoceros is the refusal of certain countries to enforce a ban on domestic trading in rhino horn.

The rhino horn is included in many doses for disorders raging from fevers to nosebleeds. Horn, like fingernails, is made of keratin and has no proven medicinal (4)___________. Traditional substitutes, such as horn from buffalo or antelope, are regarded as second best.

The battle is thought to be winnable. But it may be harder than the battle against the trade in ivory, for there is a (5)___________between the two commodities. Ivory is a luxury; rhino horn, people believe, could save the life of their child.

Điền vào số 5

The Internet has truly transformed how students do their homework. (1)______ homework today still means spending time in the library, it’s for a different reason. Rather than using books for research, students today are (2)______ to the Internet to download enormous amounts of data available online.

In the past, students were limited to their school’s (3)______ of books. In many cases, they got to the school library and found out that someone had already taken the books they needed. Nowadays, such inconvenience can be avoided since the Internet never runs out of information. Students, however, do have to

(4)______ sure that the information they find online is true. Teachers have also benefited from the homework which is done on the Internet. They do not need to carry students’ papers around with them any more. This is because online (5)______ allow students to electronically upload their homework for their teachers to read and mark. Of course, this also means that students can no longer use the excuse that the dog ate their homework!

Điền vào số 1

The Internet has truly transformed how students do their homework. (1)______ homework today still means spending time in the library, it’s for a different reason. Rather than using books for research, students today are (2)______ to the Internet to download enormous amounts of data available online.

In the past, students were limited to their school’s (3)______ of books. In many cases, they got to the school library and found out that someone had already taken the books they needed. Nowadays, such inconvenience can be avoided since the Internet never runs out of information. Students, however, do have to

(4)______ sure that the information they find online is true. Teachers have also benefited from the homework which is done on the Internet. They do not need to carry students’ papers around with them any more. This is because online (5)______ allow students to electronically upload their homework for their teachers to read and mark. Of course, this also means that students can no longer use the excuse that the dog ate their homework!

Điền vào số 2

The Internet has truly transformed how students do their homework. (1)______ homework today still means spending time in the library, it’s for a different reason. Rather than using books for research, students today are (2)______ to the Internet to download enormous amounts of data available online.

In the past, students were limited to their school’s (3)______ of books. In many cases, they got to the school library and found out that someone had already taken the books they needed. Nowadays, such inconvenience can be avoided since the Internet never runs out of information. Students, however, do have to

(4)______ sure that the information they find online is true. Teachers have also benefited from the homework which is done on the Internet. They do not need to carry students’ papers around with them any more. This is because online (5)______ allow students to electronically upload their homework for their teachers to read and mark. Of course, this also means that students can no longer use the excuse that the dog ate their homework!

Điền vào số 3

The Internet has truly transformed how students do their homework. (1)______ homework today still means spending time in the library, it’s for a different reason. Rather than using books for research, students today are (2)______ to the Internet to download enormous amounts of data available online. In the past, students were limited to their school’s (3)______ of books. In many cases, they got to the school library and found out that someone had already taken the books they needed. Nowadays, such inconvenience can be avoided since the Internet never runs out of information. Students, however, do have to (4)______ sure that the information they find online is true. Teachers have also benefited from the homework which is done on the Internet. They do not need to carry students’ papers around with them any more. This is because online (5)______ allow students to electronically upload their homework for their teachers to read and mark. Of course, this also means that students can no longer use the excuse that the dog ate their homework!

Điền vào số 4

The Internet has truly transformed how students do their homework. (1)______ homework today still means spending time in the library, it’s for a different reason. Rather than using books for research, students today are (2)______ to the Internet to download enormous amounts of data available online.

In the past, students were limited to their school’s (3)______ of books. In many cases, they got to the school library and found out that someone had already taken the books they needed. Nowadays, such inconvenience can be avoided since the Internet never runs out of information. Students, however, do have to

(4)______ sure that the information they find online is true. Teachers have also benefited from the homework which is done on the Internet. They do not need to carry students’ papers around with them any more. This is because online (5)______ allow students to electronically upload their homework for their teachers to read and mark. Of course, this also means that students can no longer use the excuse that the dog ate their homework!

Điền vào số 5

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (1)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (2) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access.

Because the federal government provides only limited funds to schools, individual school districts (3)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (4)________ abundant resources, spacious facilities, and curricular and instructional support. In (5) __________school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged.

Điền vào số 1

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (1)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (2) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access.

Because the federal government provides only limited funds to schools, individual school districts (3)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (4)________ abundant resources, spacious facilities, and curricular and instructional support. In (5) __________school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged.

Điền vào số 2

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (1)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (2) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access.

Because the federal government provides only limited funds to schools, individual school districts (3)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (4)________ abundant resources, spacious facilities, and curricular and instructional support. In (5) __________school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged.

Điền vào số 3

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (1)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (2) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access.

Because the federal government provides only limited funds to schools, individual school districts (3)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (4)________ abundant resources, spacious facilities, and curricular and instructional support. In (5) __________school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged.

Điền vào số 4

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (1)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (2) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access.

Because the federal government provides only limited funds to schools, individual school districts (3)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (4)________ abundant resources, spacious facilities, and curricular and instructional support. In (5) __________school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged.

Điền vào số 5

Any change in one part of an ecosystem can cause changes in other parts. Droughts, storms and fires can change ecosystems. Some changes harm ecosystems. If there is too (1)____ rainfall, plants will not have enough water to live. If a kind of plant dies off, the animals that feed on it may also die or move away. Some changes are good for ecosystems. Some pine forests need fire for the pine trees to reproduce. The seeds are sealed inside pinecones. Heat from a forest fire melts the seal and lets the seeds (2)_____. Polluting the air, soil, and water can harm ecosystems. Building (3)_______ on rivers for electric power and irrigation can harm ecosystems around the rivers. Bulldozing wetlands and cutting down (4)________ destroy ecosystems. Ecologists are working with companies and governments to find better ways of catching fish, cutting down trees, and building dams. They are looking for ways to get food, lumber, and other products for people (5)________ causing harm to ecosystems

Điền vào số 1

Any change in one part of an ecosystem can cause changes in other parts. Droughts, storms and fires can change ecosystems. Some changes harm ecosystems. If there is too (1)____ rainfall, plants will not have enough water to live. If a kind of plant dies off, the animals that feed on it may also die or move away. Some changes are good for ecosystems. Some pine forests need fire for the pine trees to reproduce. The seeds are sealed inside pinecones. Heat from a forest fire melts the seal and lets the seeds (2)_____. Polluting the air, soil, and water can harm ecosystems. Building (3)_______ on rivers for electric power and irrigation can harm ecosystems around the rivers. Bulldozing wetlands and cutting down (4)________ destroy ecosystems. Ecologists are working with companies and governments to find better ways of catching fish, cutting down trees, and building dams. They are looking for ways to get food, lumber, and other products for people (5)________ causing harm to ecosystems

Điền vào số 2

Any change in one part of an ecosystem can cause changes in other parts. Droughts, storms and fires can change ecosystems. Some changes harm ecosystems. If there is too (1)____ rainfall, plants will not have enough water to live. If a kind of plant dies off, the animals that feed on it may also die or move away. Some changes are good for ecosystems. Some pine forests need fire for the pine trees to reproduce. The seeds are sealed inside pinecones. Heat from a forest fire melts the seal and lets the seeds (2)_____. Polluting the air, soil, and water can harm ecosystems. Building (3)_______ on rivers for electric power and irrigation can harm ecosystems around the rivers. Bulldozing wetlands and cutting down (4)________ destroy ecosystems. Ecologists are working with companies and governments to find better ways of catching fish, cutting down trees, and building dams. They are looking for ways to get food, lumber, and other products for people (5)________ causing harm to ecosystems

Điền vào số 3

Any change in one part of an ecosystem can cause changes in other parts. Droughts, storms and fires can change ecosystems. Some changes harm ecosystems. If there is too (1)____ rainfall, plants will not have enough water to live. If a kind of plant dies off, the animals that feed on it may also die or move away. Some changes are good for ecosystems. Some pine forests need fire for the pine trees to reproduce. The seeds are sealed inside pinecones. Heat from a forest fire melts the seal and lets the seeds (2)_____. Polluting the air, soil, and water can harm ecosystems. Building (3)_______ on rivers for electric power and irrigation can harm ecosystems around the rivers. Bulldozing wetlands and cutting down (4)________ destroy ecosystems. Ecologists are working with companies and governments to find better ways of catching fish, cutting down trees, and building dams. They are looking for ways to get food, lumber, and other products for people (5)________ causing harm to ecosystems

Điền vào số 4

Any change in one part of an ecosystem can cause changes in other parts. Droughts, storms and fires can change ecosystems. Some changes harm ecosystems. If there is too (1)____ rainfall, plants will not have enough water to live. If a kind of plant dies off, the animals that feed on it may also die or move away. Some changes are good for ecosystems. Some pine forests need fire for the pine trees to reproduce. The seeds are sealed inside pinecones. Heat from a forest fire melts the seal and lets the seeds (2)_____. Polluting the air, soil, and water can harm ecosystems. Building (3)_______ on rivers for electric power and irrigation can harm ecosystems around the rivers. Bulldozing wetlands and cutting down (4)________ destroy ecosystems. Ecologists are working with companies and governments to find better ways of catching fish, cutting down trees, and building dams. They are looking for ways to get food, lumber, and other products for people (5)________ causing harm to ecosystems

Điền vào số 5