Does soil contain air? If yes, how is the air trapped in soil useful to certain organisms?

Answer these question on earthworm.

How do earthworms help air enter the soil?

Read the passage and answer the following questions.

Water Pollution

Water pollution is the contamination of water bodies and is harmful to the health of humans and animals. It may not damage our health immediately but can be harmful after long-term exposure. Different forms of pollutants affect the health of animals in different ways: (a) heavy metals from industrial processes can accumulate in nearby lakes and rivers. These are toxic to marine life such as fish and shellfish, and subsequently to the humans eat them. (b) Microbial pollutants from sewage often result in infectious diseases that infect aquatic life and terrestrial life through drinking water. Microbial water pollution is the major problem in the developing world, with diseases such as cholera and typhoid being the primary cause of infant mortality. (c) Organic matter and nutrients cause an increase in aerobic algae and depletes oxygen from the water column. This causes the suffocation of fish and other aquatic organisms. (d) Sulfate particles from acid rain can cause harm to the health of marine life in the rivers and lakes it contaminates, and can result in mortality. (e) Suspended particles in freshwater reduces the quality of drinking water for humans and the aquatic environment for marine life. Suspended particles can often reduce the amount of sunlight penetrating the water, disrupting the growth of photosynthetic plants and microorganisms.

How does the oxygen level decrease in the water? 

Choose the correct word from the list given below:

List: nitrogen, carbon dioxide, wind, oxygen, earth.

Write an activity to show that soil contains air.

How do the following organisms fulfil their oxygen requirements?

i. Fish             

ii. Small organisms found in soil.