What are some similarities between nerves and hormones?

The biggest difference between the two is that the nervous system uses electrical impulses to send signals through neurons, whereas the hormonal system uses chemical messengers transported into blood plasma to target cells. While endocrine system is slow, nervous impulse is immediate/rapid. Hormones are transported chemically through blood, nervous impulses are transported electrochemically through nerve fibres. Hormones affect different organs of the body and has a widespread effect, while nervous impulses afeect only a particular part of the body. Hormonal effect is long lasting whereas nervous effect is short lived. Hormones can bring about a metabolic change but nervous impulse impulses cannot bring about a metabolic change.

"a.) well–developed vascular system."

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.