6 E 1 2

Which properties are MOST important to sustaining life on Earth?

• 1 and 2

• 2 and 3

• 3 and 4

• 4 and 5

Which of these provide the BEST evidence that life could develop on Mars?

• its atmospheric gases

• its surface temperatures

• its craters and rocky surface

• its ice and organic molecules

Fish can live in lakes that are frozen because liquid water remains below the ice at the

surface. Which of these describes a property of water that allows some liquid water to

remain in frozen lakes?

• Water can dissolve many different substances.

• Water is less dense as a solid than as a liquid.

• Water has a Mohs hardness of about 2 when it is frozen.

• Water holds less air at higher temperatures.

Organisms can live on Earth because of Earth’s location in the solar system. How does Earth’s distance from the Sun MOST affect Earth’s water and enable life to exist?

• It permits liquid water.

• It allows water to freeze.

• It changes water’s specific gravity.

• It allows water to be salty or fresh.

How does gravity support life on Earth?

• by forcing Earth to continuously spin on its axis, which contributes to

  day and night

• by causing changes in the distance between Earth and the sun, which contributes to the seasons

• by keeping water and gases in the atmosphere close to Earth’s

  surface, which contributes to life processes

• by preventing meteors and comets from hitting Earth’s surface, which protects living organisms from space fragments

Which contributes to Earth’s ability to sustain life?

• The atmosphere allows all of the sun’s radiation to enter due to

  Earth’s distance from the sun.

• The atmosphere prevents all space debris from reaching the surface

  due to the ozone layer.

• The atmosphere is extremely thin due to the temperatures of the sun.

• The atmosphere is breathable due to the unique mixture of gases.

Which fact BEST explains why there is life on Earth but not on the Moon?

• The Moon has no gravity.

• The Moon does not go around the Sun.

• The Moon has little water and oxygen.

• The Moon is much smaller than Earth.

What is significant about the discovery of water on Mars?

• It proves there is life on Mars.

• It provides evidence there may be life on Mars.

• It proves there was an advanced civilization on Mars.

• It provides evidence of an advanced civilization on Mars.

Which table correctly compares the physical characteristics of the Sun and Earth?

• A

• B

• C

• D

Garden plants on Earth require four resources to stay alive: soil, air, water, and sunlight.

How many of these resources are necessary for life to exist on another planet or the Moon?

• 4

• 3

• 2

• 1