In line 20, the word “launched” is closest in meaning to _______.

The word “grumpy” in paragraph 1 is closest in meaning to

What does the author say about Teflon?

What was keeping Martha inside?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

A large number of inventions require years of arduous research and development before they are perfected. For instance, Thomas Edison had to make more than 1,000 attempts to invent the incandescent light bulb before he finally succeeded. History is replete with numerous other examples of people trying, yet failing to make inventions before they eventually succeeded. Yet some inventions have come about not through hard work but simply by accident.

In most cases, when someone unintentionally invented something, the inventor was attempting to create something else. For example, in the 1930s, chemist Roy Plunkett was attempting to make a new substance that could be used to refrigerate items. He mixed some chemicals together. Then, he put them into a pressurized container and cooled the mixture. By the time his experiment was complete, he had a new invention. It was not a new substance that could be used for refrigeration though. Instead, he had invented Teflon, which is today most commonly used to make nonstick pots and pans. Similarly, decades earlier, John Pemberton was a pharmacist in Atlanta, Georgia. He was attempting to create a tonic that people could use whenever they had headaches. While he was not successful in that endeavor, he managed to invent Coca - Cola, the world - famous carbonated soft drink.

Scientists have also made crucial discoveries by accident when they were conducting experiments. In 1928, Alexander Fleming discovered penicillin, an antibiotic, in this manner. He discovered some mold growing in a dish with some bacteria. He noticed that the bacteria seemed to be avoiding the mold. When he investigated further, he determined some of the many useful properties of penicillin, which has saved millions of lives over the past few decades. Likewise, in 1946, scientist Percy Spencer was conducting an experiment with microwaves. He had a candy bar in his pocket, and he noticed that it suddenly melted. He investigated and learned the reason why that had happened. Soon afterward, he built a device that could utilize microwaves to heat food: the microwave oven.

Question 8: Which title best summarizes the main idea of the passage?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to Indicate the correct answer to each of the questions.

There is a wide range of organisms by their population whose lives mostly depend on how they hunt or are hunted. And most living organisms have some way of protecting themselves from natural predators. Some mammals, like the platypus, carry internal toxins to transmit to predators via biting or other means, and some plants protect themselves by being poisonous. The African crested rat was originally thought to be poisonous because predators that tried to eat it often became paralyzed. But scientists have recently learned that's not actually the case.

The crested rat chews on the poisonous bark of a certain tree, and then smears the chewed-up substance onto its fur, where a strip of special quill-like hairs soaks up the poisonous mixture. Though similar to a porcupine's, the quills do differ: whereas the porcupine defends itself by poking predators, the African rat uses its quill-like hairs to deliver poison to them. When a predator comes after it, instead of running away, the rat stays put and parts its hair to reveal the strip of fur on its back where the poison is being stored. That raised strip is the first thing that receives a bite, and the poison inside disables the predator. These hair tubes are unusual. In fact, scientists do not know of another animal that uses plant poison in this way.

Scientists are puzzled that the rat doesn't appear to be affected by the poison. Because it affects

heartbeat regulation, understanding how the rat can keep its heart rate regulated effectively while using the poison could help scientists develop new medicines for people with heart trouble. And they hope that those suffering from heart diseases will benefit from this.

What is the main purpose of the passage?