Problem: Tom and Andy are two old friends. Tom was infected with HIV 20 years ago, and Andy has been helping him ever since. Andy is as healthy as an ox. Given the paragraph above, please answer correctly the following question: Which friend has a weaker immune system? Hint: HIV , or human immunodeficiency virus, causes AIDS. AIDS stands for "acquired immune deficiency syndrome." It is a condition that causes death and does not have a known cure. AIDS usually develops 10 to 15 years after a person is first infected with HIV. The development of AIDS can be delayed with proper medicines. The delay can be well over 20 years with the right medicines. Today, individuals who acquire HIV after 50 years of age can expect to reach an average human life span.

A: Tom

Problem: Two students studied the atmosphere of Earth and other planets from our solar system. Zack learned about Earth's atmosphere, while Ken learned about the atmospheric conditions on planet Venus. Given the paragraph above, please answer correctly the following question: Which student learned less about carbon dioxide clouds? Hint: Clouds on Earth are made of water vapor. Venus's clouds are a lot less pleasant. They are made of carbon dioxide, sulfur dioxide and large amounts of corrosive sulfuric acid! The atmosphere of Venus is so thick that the pressure on the surface of Venus is very high. In fact, it is 90 times greater than the pressure at Earth's surface! The thick atmosphere causes a strong greenhouse effect. As a result, Venus is the hottest planet. Even though it is farther from the Sun, Venus is much hotter even than Mercury. Temperatures at the surface reach 465C (860F). That's hot enough to melt lead!

A: Zack

Problem: To reenact James Watt's experiment, John sealed some water in a container. He called this stage of his experiment as stage A. Then he started heating the water in the sealed container. He labeled this stage as stage B. Once the temperature reached hundred degree centigrade, he added more heat to it. He called this stage as stage C. Once all the water has turned into steam, he kept adding heat to it. He called this last stage of is experiment as stage D. Given the paragraph above, please answer correctly the following question: In which stage the water would have less kinetic energy, stage A or stage B? Hint: Continued heating of the water after the ice has completely melted will now increase the kinetic energy of the liquid molecules and the temperature will rise. Assuming that the atmospheric pressure is standard, the temperature will rise steadily until it reaches 100C. At this point, the added energy from the heat will cause the liquid to begin to vaporize. As with the previous state change, the temperature will remain at 100C while the water molecules are going from the liquid to the gas or vapor state. Once all the liquid has completely boiled away, continued heating of the steam (remember the container is closed) will increase its temperature above 100C.

A: stage A

Problem: Danny started weight lifting two years ago, he wanted to be bigger. His brother Arnie preferred athletic competitions such as running, so he became a runner. Given the paragraph above, please answer correctly the following question: Which brother gradually increased the size of his muscles? Hint: In exercises such as weight lifting, skeletal muscle contracts against a resisting force (see Figure below ). Using skeletal muscle in this way increases its size and strength. In exercises such as running, the cardiac muscle contracts faster and the heart pumps more blood. Using cardiac muscle in this way increases its strength and efficiency. Continued exercise is necessary to maintain bigger, stronger muscles. If you don't use a muscle, it will get smaller and weakerso use it or lose it.

A:
Danny