Biologic activity can change the amount of water in the atmosphere. For example, plants release water vapor into the atmosphere through the process of transpiration. This water vapor can then condense to form clouds and precipitation. In addition, biologic activity can also affect the amount of water in the soil. For example, the roots of plants can help to hold water in the soil, while the activities of earthworms and other organisms can help to aerate the soil and improve drainage. Biologic activity can also affect the amount of water in the oceans. For example, the growth of coral reefs can help to protect coastlines from erosion and storm damage.