unit 2 lesson 5

Question 1

carbon cycle

Answer 1

the process in which carbon cycles between the atmosphere, land, water, and organisms

Question 2

nitrogen cycle

Answer 2

the process in which nitrogen transfers between the atmosphere, bacteria, and other organisms

Question 3

phosphorus cycle

Answer 3

the process in which phosphorus moves from the environment to living organisms and back into the environment

Question 4

Water Cycle

Answer 4

The main way water becomes fresh is through the water cycle.

Question 5

Carbon-Oxygen Cycle

Answer 5

Carbon is important because plants need the carbon in carbon dioxide to do photosynthesis. In the carbon cycle, carbon from the air gets inside living organisms and then returns to the air. The carbon cycle transfers carbon between the atmosphere, land, water, and organisms. Although the carbon cycle can take many different paths, below is one example of a carbon cycle occurring in a forest ecosystem.

Question 6

Carbon Dioxide-Oxygen Cycle

Answer 6

Part of the carbon cycle is the carbon dioxide-oxygen cycle. This is one of the most important cycles for the survival of plants and animals. Plants and animals need certain gases to survive. Plants need carbon dioxide and oxygen, and most organisms need oxygen. These gases are cycled in the carbon dioxide-oxygen cycle.