During _______, the sun's heat turns liquid into vapor.

In the process of _______, the vapor cools and returns into liquid.

The water that falls from the atmosphere to the land and ocean is called ________.

Most water falls into the ocean but some water falls on land and flows into streams, rivers, and lakes. This is called _______.

Some water that falls on land seeps into the Earth. This is called _______.

How are you doing on the water cycle?

The exchange of carbon between the environment and living things is called ________.

_______ is the basis of the carbon cycle.

Plants use _______ to make sugars they can eat.

Most animals get the carbon and energy they need from eating _______.

Carbon goes back into the environment when sugar molecules are broken down to release energy. This process is called _________.

The breakdown of substances into simpler molecules is called ________.

________ is the process of burning a substance, such as wood or fossil fuels.

How are you doing on the carbon cycle

The movement of nitrogen between the environment and living things is called ________.

About ____% of the Earth's atmosphere is nitrogen gas.

How are you doing on the nitrogen cycle?

The regrowth of a burned area is called ________.

If enough organisms die on a rock the rock can be transformed into soil. This is called ________.

If soil is left intact, the original community may regrow in stages called ________.

___________ is a species that colonizes an uninhabited area and starts the process of succession.

As a community matures, it may be taken over by a well-adapted, slow-growing ________.