Which of the following best explains why ecosystems need a continual influx of new energy?
a. photosynthesis feeds herbivores, carnivores, and decomposers.
b. as energy is recycled, a small amount is lost as heat.
c. energy flows through an ecosystem and cannot be recycled.
d. cellular respiration does not feed back into other processes.

✿   this landform has a high elevation and a high relief

✿   this landform is a mountain

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.