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 1. (c) Soil erosion: Removal of the fertile top layer of soil by wind, water, or human activities.

(d) Deforestation: Large-scale cutting of forests by humans.

10. Decomposers are organisms that break down dead plants and animals. Examples: Bacteria and Fungi. They return nutrients to the soil and keep the forest clean.

14.Forests prevent floods by holding soil with roots, absorbing rainwater, and reducing fast water flow.

15. Forests maintain oxygen and carbon dioxide balance by absorbing carbon dioxide and releasing oxygen during photosynthesis.

Ch 13

10. Four water-borne diseases caused by drinking contaminated water: 1. Cholera 2. Typhoid 3. Dysentery 4. Hepatitis A

21 .Poor sanitation allows germs to grow and contaminate water, food, and surroundings.

These germs spread diseases.

Proper sanitation and cleanliness prevent the spread of infections and keep people healthy.