Answer the following question given this paragraph: Cynodonts probably gave rise to mammals about 200 million years ago. However, they are not considered to be mammals themselves. In fact, competition with early mammals may have led to their extinction. They went extinct sometime during the Jurassic or Cretaceous Period. Q: Competition with what emerging animal group may have led to extinction of cynodonts about 200 million years ago? Choices: - reptiles - amphibians - insects - mammals A:
mammals
Answer the following question given this paragraph: We know that the Universe is expanding. Astronomers have wondered if it is expanding fast enough to escape the pull of gravity. Would the Universe just expand forever? If it could not escape the pull of gravity, would it someday start to contract? This means it would eventually get squeezed together in a big crunch. This is the opposite of the Big Bang. Q: Astronomers have wondered if the universe is expanding fast enough to escape the pull of what? Choices: - kinetic energy - Coreolis effect - light - gravity A:
gravity
Q: Answer the following question given this paragraph: Thunderstorms grow where ground temperatures are extremely high. Q: Are thunderstorms more likely where the ground temperatures are extremely high or extremely low? Choices: - somewhat low - somewhat high - extremely low - extremely high A:
A: extremely high
Question: Answer the following question given this paragraph: Law of Refraction Figure 25.12 shows how a ray of light changes direction when it passes from one medium to another. As before, the angles are measured relative to a perpendicular to the surface at the point where the light ray crosses it. (Some of the incident light will be reflected from the surface, but for now we will concentrate on the light that is transmitted. ) The change in direction of the light ray depends on how the speed of light changes. The change in the speed of light is related to the indices of refraction of the media involved. In the situations shown in Figure 25.12, medium 2 has a greater index of refraction than medium 1. This means that the speed of light is less in medium 2 than in medium 1. Note that as shown in Figure 25.12(a), the direction of the ray moves closer to the perpendicular when it slows down. Conversely, as shown in Figure 25.12(b), the direction of the ray moves away from the perpendicular when it speeds up. The path is exactly reversible. In both cases, you can imagine what happens by thinking about pushing a lawn mower from a footpath onto grass, and vice versa. Going from the footpath to grass, the front wheels are slowed and pulled to the side as shown. This is the same change in direction as for light when it goes from a fast medium to a slow one. When going from the grass to the footpath, the front wheels can move faster and the mower changes direction as shown. This, too, is the same change in direction as for light going from slow to fast. Q: What law explains how the change in direction of the light ray depends on how the speed of light changes, which in turn is related to the indices of refraction of the media involved? Choices: - Boyle's law - Born's law - Newton's first law - law of refraction A:
Answer: law of refraction
*Question*
Answer the following question given this paragraph: Only hurricanes cause more damage than earthquakes. Only one source of earthquake damage is ground shaking. More damage may be done from the tsunami, fires, and landslides that can happen afterwards. Communities along faults can prepare for earthquakes. One way is to use earthquake-safe construction methods and to make older buildings stronger. If you live in earthquake country, it is important to secure heavy objects and put together an emergency kit. Q: What is the only natural phenomenon that causes more damage than earthquakes? Choices: - volcanos - blizzards - landslides - hurricanes A:
**Answer**
hurricanes
*Question*
Answer the following question given this paragraph: Oxidation can be defined as the addition of oxygen to a molecule or the removal of hydrogen from a molecule. When an alkane is heated in the presence of an appropriate catalyst, it can be oxidized to the corresponding alkene in a reaction called a dehydrogenation reaction. Two hydrogen atoms are removed in the process. The alkene can be further oxidized to an alkyne by the removal of two more hydrogen atoms. Q: What is the addition of oxygen to a molecule or the removal of hydrogen from a molecule called? Choices: - precipitation - evaporation - ionization - oxidation A:
**Answer**
oxidation