A pond, rich in various microorganisms, dries up due to drought. How will the amoeba in the pond protect themselves from this unfavorable condition?

The correct answer is : by secreting a thick cell wall which encloses many amoebae in it to prevent loss of water, forming a cyst until favorable conditions emerge

Explanation:

Amoeba protects itself in unfavorable conditions such as drought or less water or food availability. Amoeba takes back all its pseudopodia and secretes a thick cell wall which form three layer hard covering arout amoeba body.

This hard covering is known as the cyst  and this process known as the encystation. Amoeba remain in this cyst form until favorable conditions emerge.

Thus, the correct answer would be - by secreting a thick cell wall which encloses many amoebae in it to prevent loss of water, forming a cyst until favorable conditions emerge

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.