Presence of Oxygen in Soil and Water

Since, it is known that plants and animals living in soil and water require also oxygen to survive , therefore it must be present there.

Activity to show that Air is contained in Water

1. Take some water in a container.
2. Heat the water.
3. Before the water begins to boil we see tiny bubbles in the container.
4. These bubbles have air dissolved in water.

Note - Air dissolved in water helps aquatic animals like fish to breathe.

Activity to show that Soil is contained in Water

1. Take some lump of soil in a beaker.
2. Add Water.
3. We see bubbles coming out of soil.
4. This indicates the presence of air in the soil.

Note- This air helps the animals living in the soil to breathe. 

For Example - Earthworms.