Answer:
Those fish were prey.
Explanation:
It is clear to see that the utilization of full body plates drastically increased and the usage of half body plates dramatically decreased. This is likely showing that these fish were heavily targeted, and therefore, needed to use better defensive mechanisms; hence the usage of full body plates compared to two-thirds or half. This is all showing these fish were likely prey for bigger fish, or perhaps non-marine predators as well.
The correct answer is option B, that is, there is a higher solute concentration inside so water is moving into the cell constantly.
The contractile vacuole functions to pump out an extra amount of water from the cell. Paramecium lives in freshwater, where the water exhibits lower solute concentration in comparison to the cytoplasm within the cell. Therefore, due to osmosis, the water will flow within the cell.
The extra amount of water can be accumulated at the contractile vacuole and then be withdrawn out. The frequency and rhythm of the contraction rely on the surrounding and also on the number of contractile vacuoles present.