Question

In terms of osmoregulation, freshwater fish __________. must drink a lot of water and excrete excess salts must have dilute urine and consume salt in their diet have no osmosregulation issues maintain high levels of urea are isoosmotic with their environment

Answer 1

In terms of osmoregulation, freshwater fish must have dilute urine and consume salt in their diet.

Answer: Option B

Step-by-step explanation:

Osmoregulation is a major criteria of that is required for the living of the fishes in the water, the balance of the ionic content between the external water environment of the fish and its internal environment is required for its healthy survival.

Answer 2

Osmosis is the process where there is some balancing of concentrations with the solvent moving. In this case, we have that within the fish and the water, the salt content is different; this creates a flow of water. IN THE SEA, the seawater has more salt and this creates a flow towards the sea from the cells of the fish; choice a WOULD BE correct in this case.
In freshwater though, we have that the fish has more salt inside it (higher concentration) than the surrounding water. Hence, water goes in the fish and the fish needs to conserve its salts in the form of urea; thus, they must consume lots of salt and have low urine. THE CORRECT ANSWER THUS IS B.

P.S. comment on osmoregulation: it does not happen when fishes are isotonic to their environment, namely they have the concentration of the water surrounding them; then no flow is created.