Animals are not able to convert fatty acids into carbohydrates. the net synthesis of one mole of oxaloacetate from two moles of acetyl‑coa by the citric acid cycle does not occur because one mole of oxaloacetate is used in the cycle for each one generated. plants are able to convert two moles of acetyl‑coa into one mole of oxaloacetate with only two additional enzymes not found in animals. this process is called the glyoxylate cycle, and it occurs in organelles called glyoxysomes. classify the enzymes based on whether they are found only in plants or are found in both plants and animals.

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.