Q: Why do mountain climbers at high elevations use oxygen tanks to help them breathe? OPTIONS:
- At high elevations the ozone layer draws oxygen out of the atmosphere.
- The atmosphere is less dense at higher elevations so there is less oxygen available.
- Oxygen is heavier than the other gases in the atmosphere and sinks to lower elevations.
- Radiation from the Sun splits oxygen molecules into atoms making the oxygen unbreathable.
A: The atmosphere is less dense at higher elevations so there is less oxygen available.

Q: The pull of gravity on Earth is a direct result of the OPTIONS:
- mass of Earth.
- magnetic field of Earth.
- rotation of Earth on its axis.
- weight of Earth's atmosphere.
A: mass of Earth.

Q: A large cold front is moving past the school on a hot, humid summer day. Which best describes the type of weather as the cold front passes by? OPTIONS:
- A drought
- A monsoon
- A hurricane
- A thunderstorm
A: A thunderstorm

Q: What kingdom contains organisms that are multicellular, have no chlorophyll, and absorb nutrients from decaying tissue? OPTIONS:
- Fungi
- Plantae
- Protista
- Animalia
A:
Fungi