1. Identify the ecological roles of the fish and the shark. 2. Identify the type of symbiosis that exists with these two organisms. Explain the
reason for your choice.
3. Identify a second type of symbiosis and what would have to change in their
relationship to be that type of symbiosis.

Sharks acts as predators whereas fish act as prey.

Explanation:

Sharks acts as predators that play an important role in the ecosystem by controlling the population many marine animals from causing damaged to the ecosystem whereas fish is considered as the primary consumers that provides food to the secondary consumers and helps to maintain balance in the ecosystem. Mutualism, predation and commensalism are the types of symbiosis that present between fish and shark. Remoras fish feed on the parasites present on the shark's skin and in its mouth which benefits the shark as well as the fish whereas in commensalism,  the pilot fish takes benefit from the shark but there is no known effect on the shark.

d. groundwater flows through the subsoil and deposits minerals.

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.