Which characteristic best distinguishes glycolysis and the krebs cycle from the electron transport chain?
a. the amount of atp produced
b. the location in which they occur
c. whether glucose is broken down
d. whether they occur in plants or animals

The correct answer is A. the amount of ATP produced.

The three reactions of the aerobic respiration in order are glycolysis, Kreb's cycle and the electron transport chain.

These processes are common to plants and animals and in the first step of respiration which is glycolysis the glucose breaks down.  Only glycolysis occurs in the cytoplasm of the cell while both Kreb's cycle and electron transport chain occurs in mitochondria. In the question the difference is asked between glycolysis and krebs cycle to the electron transport chain.  The initial two processes differ to the electron transport chain in terms of the number of ATP molecules generated. Both  glycolysis and the Kreb's cycle generate 2 ATP each respectively but the electron transport chain produces a net of 34 ATP molecules and therefore, electron transport chain differs from glycolysis and  Kreb's cycle in terms of the amount of ATP produced.

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.