Which of the following best describes how the amount of DNA in the cell changes during M phase? A
The amount of DNA doubles as the DNA is replicated.
B
The amount of DNA slightly increases as a result of new organelle synthesis.
С
The amount of DNA does not change while the cell grows.
D
The amount of DNA is halved as the cell divides into two daughter cells.

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.