Why wouldn’t the water cycle constantly adds pollution to the air be important in the water cycle

This wouldn't be important because the water cycle is simply a series of events that occur starting from Evaporation, condensation, sublimation, precipitation, transpiration, run off, and lastly infiltration. Though you may think that through a certain step the water is adding pollution to the air, this is not something that is being examined or asked of you to identify when specifically dealing with the water cycle alone. Hope that answers your question.

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.