The is considered the autonomic control center of the body due to its regulation of hormone secretion, thermoregulation, food and water intake, and circadian rhythms.

hypothalamus

Explanation:

The hypothalamus is a very vital part of the brain, which is situated at the base of the brain, and it is connected to the pituitary gland by nervous and chemical pathways. The hypothalamus is responsible for the stimulation of the release of several hormones of the body as well as regulates the activities most autonomic nervous system. Functions such as circadian rhythms, body temperature, behavior, release of hormones, homeostasis are controlled by the hypothalamus.

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.