A scientist was investigating why several fish caught from a local stream displayed similar mutations. He found that the water temperature of the stream was elevated since an industrial plant began discharging heated water into the stream. The scientist concluded that increased water temperature during the egg phase led to the mutation in the fish. According to this conclusion, the mutation was caused by

Increased water temperature caused by the industrial plant.

Explanation: this is explained in the text lol.

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.