1. Photosynthesis & Cellular Respiration
26. Which two processes are responsible for keeping the percentage of atmospheric oxygen at relatively constant levels? A. circulation and coordination B. respiration and coordination C. respiration and photosynthesis D. photosynthesis and circulation

2. Photosynthesis & Cellular Respiration
27. A human activity that could significantly decrease the amount of carbon dioxide in the air is A. increasing the use of fossil fuel B. controlling insect pests that eat stored grain C. burning garbage and trash to generate electricity D. preserving and expanding forest habitats that shelter wildlife

3. Photosynthesis & Cellular Respiration
28. The energy used to obtain, transfer, and transport materials within an organism comes directly from A. ATP B. DNA C. Sunlight D. starch

4. Photosynthesis & Cellular Respiration
29. Changes in water pressure within guard cells cause the cells to open or close the stoma. This response helps the plant maintain homeostasis by — A. stabilizing the plant’s temperature through the evaporation of water B. regulating the amount of water the plant loses during transpiration C. allowing oxygen needed for photosynthesis to enter the plant D. enabling the plant to release more carbon dioxide at night for photosynthesis

5. Photosynthesis & Cellular Respiration
30. Which of the following correctly describes how a diagram of cellular respiration would differ from a diagram of photosynthesis? F. The cellular-respiration diagram would show electromagnetic waves as the final product. G. The cellular-respiration diagram would show glucose as the main source of energy. H. The cellular-respiration diagram would show energy stored in large protein molecules. J. The cellular-respiration diagram would show water as the main source of chemical energy.

6. Photosynthesis & Cellular Respiration
31.

7. Photosynthesis & Cellular Respiration
32.

8. Photosynthesis & Cellular Respiration
33. Which process illustrates a feedback mechanism in plants? A. Chloroplasts take in more nitrogen, which increases the rate of photosynthesis. B. Chloroplasts release more oxygen in response to a decreased rate of photosynthesis. C. Guard cells change the size of leaf openings, regulating the exchange of gases. D. Guard cells release oxygen from the leaf at night.

9. Photosynthesis & Cellular Respiration
34.

10. Photosynthesis & Cellular Respiration
35. The diagram below represents a cycling of
materials.