1. Cycles Over and Over Again Nitrogen Water Carbon

2. TEKS 5.6B What is the significance of the water, carbon, and nitrogen cycles?

3. Which of the following is necessary for plants to make sugars during photosynthesis? A.Insects B.Sunlight C. Soil D. Nitrogen

4. The correct answer is B. A plant uses the energy from sunlight to make sugars from water and carbon dioxide.

5. These answers are incorrect because… A. Insects help in pollination. C. Soils provide nutrients for land plants. D. Nitrogen is a nutrient.

6. Plants in the oceans could provide all of these resources to animals except? A. carbon dioxide B. food C. oxygen D. habitats

7. The correct answer is A because …. Animals do not need carbon dioxide as a resource. Animals release carbon dioxide during respiration.

8. These answers are incorrect because... B. Plants are food for animals. C. Plants use carbon dioxide during photosynthesis to produce sugars and oxygen. D. Plants may provide habitats for animals.

9. The water cycle is a significant factor to all of the following actions except: A. erosion B. living organisms C. deposition D. eruption of volcanoes

10. The correct answer is D. Volcanoes are the result of forces within the earth and not totally of the water cycle.

11. These answers are incorrect because: A.The movement of surface water often causes erosion and is often a result of precipitation, a significant part of the water cycle. B. Water is necessary for life and Earth receives water as a direct result of the water cycle. C. When moving water (caused by the elements of the water cycle) slows down or stops, sediments are dropped.