Keeps Earth's temperature stable and cool.

Is necessary for life as we know it.

Affects temperature of a planet.

Earth's _____ helps protect life from ultraviolet radiation.

Earth's atmosphere is mostly made up of the gases _____ and _____.

There is some evidence to suggest that Mars once had liquid _____ though now it may be trapped as _____.

If Earth were much smaller than it is now, it would not support life because it would not have enough mass to -

Ozone contributes to supporting life on earth by blocking -

Which of the following discoveries about Mars suggests conditions that may have once supported life? Mars has -

Space stations require an oxygen system because the atmosphere in space -

Which of the following accommodations on the space station is used by astronauts to combat the effects of microgravity on their bones?

Radios are not required for astronauts to talk to each other when they are in the same room inside the space station because -

Astronauts wear thick gloves when they perform a space walk outside the space station. The gloves provide protection against -

Spacesuits have layers that have high capacity for thermal insulation in order to -

What design element of an astronaut's spacesuit protects him or her from micrometeoroids, which are tiny bits of space debris travelling at high speeds?

How do astronauts counteract the effects of microgravity on their bones while they are in space?

The living quarters and equipment used to protect astronauts while in space

The protective gear that protects astronauts from the cold, airless environment of space.

A man-made laboratory that is placed in space for research.