Assertion (A): Earth is a watery planet that supports life.

Reason (R): Distribution of water is responsible for moderating the surface condition of the earth.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R does not explain A.
3. A is true but R is false.
4. A is false but R is true.

Earth has a very hospitable temperature and mix of chemicals that have made life abundant here. Most notably, earth is unique in that most of our planet is covered in liquid water, since the temperature allows liquid water to exist for extended periods of time. Besides liquid water and temperature identify the other features of our planet that make it great for sustaining life?

1. Presence of an atmosphere
2. Solid crust
3. Distance from the sun
4. All of the above.

What term refers to a self-regulating and self-sustaining unit of the biosphere?

1. Ecosystem
2. Food cycle
3. Biome
4. Ecology

Name the cycle through which solar energy moves from non-living to living organisms and back.

1. Carbon cycle
2. Nitrogen cycle
3. Nutrition cycle
4. Energy cycle