11. The diagram below indicates the altitude of Polaris as measured at three locations in the Earth's Northern
Hemisphere,
20
Corsi
What is the best inference to be drawn from these
observations?
(1) the Earth has an elliptical orbit
(2) the Earth rotates 15" per hour
(3) the Earth has a curved surface
(4) the Earth revolves around the sun

you can have just about every answer you can think of

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.