Marine dead zones can form when nutrient run-off causes certain types of algae to grow very quickly and then die off. As dead algae decompose, oxygen is removed from the water. With
less oxygen available, fish and other marine animals can die. What would be one practical
way to reduce marine dead zones?
A Pump oxygen into the water using equipment on fishing vessels.
B Add bacteria that are able to eat the fast-growing algae.
C Prevent fertilizer and other wastes from entering rivers and streams.
D Harvest marine fish in dead zone areas to reduce oxygen use.

voluntary muscles are controlled by the cerebellum.

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.