Directions
Read each item carefully. Choose the letter of the BEST answer.

1. The oxygen and carbon dioxide cycle is the movement of gases by the
processes of ___and ___.
A. breathing in and breathing out
B. plants and animals
C. respiration and photosynthesis
D. oxygen and carbon dioxide

2. Oxygen is a gas produced by ___ and needed by ___.
A. animals ... plants
B. plants ... animals
C. carbon dioxide ... photosynthesis
D. photosynthesis ... carbon dioxide

3. Carbon dioxide is a gas released by ___ and used by ___.
A. plants ... animals
B. photosynthesis ... carbon dioxide
C. animals ... plants
D. carbon dioxide ... photosynthesis

4. Plants need ___ , ___ , and___ for photosynthesis to happen.
A. food, water, and carbon dioxide
B. food, water, and oxygen
C. sunlight, water, and oxygen
D. sunlight, water, and carbon dioxide

5. Humans and other animals exhale ___ during ___
A. carbon dioxide... respiration
B. oxygen... carbon dioxide
C. carbon dioxide... photosynthesis
D. oxygen... photosynthesis​