Question

1. most pollutants that enter estuaries break down over time, yet they are still considered a problem because mark only one oval. a. the pollutants eventually enter the ocean b. it is the volume of the pollutants, more than the time factor, that harms estuaries. c. the pollutants break down into still more dangerous toxins d. none of the above 20. what distinguishes nekton from benthos? mark only one oval. a. one lives in a freshwater ecosystem and the other lives in salty water. b. one swims freely and the other often lives attached to a hard surface. c. one is a predator and the other is a primary producer d. none of the above 21. wetlands perform several important environmental functions. which do you think is most crucial? defend your answer. 22. give one example of how coral reefs are threatened by human activities and one example of how estuaries are threatened by human activities.

Explanation:

1. The volume of pollutants entering estuaries is a major issue as it can overwhelm the ecosystem's ability to handle them, even if they break - down over time.
2. Nekton are free - swimming organisms like fish, while benthos often live attached to the substrate such as mussels on the ocean floor.
3. Wetlands are crucial for water purification as they filter out pollutants and excess nutrients from water through physical, chemical, and biological processes. For example, plants in wetlands can absorb heavy metals and bacteria can break down organic matter.
4. Coral reefs are threatened by overfishing, which can disrupt the balance of the reef ecosystem. Estuaries are threatened by industrial waste and sewage disposal, which introduce harmful pollutants into the water.

Answer:

1. b. It is the volume of the pollutants, more than the time factor, that harms estuaries.
2. b. One swims freely and the other often lives attached to a hard surface.
3. Water purification. Wetlands filter pollutants and excess nutrients from water through physical, chemical and biological processes.
4. Coral reefs: Overfishing. Estuaries: Industrial waste and sewage disposal.