Osmosis multiple choice

[Anne Boleyn]

Hey guys! How do you solve this question ? - apparently the answer is B yet I don’t don’t understand why.

Fresh water fish have tissue that is hypertonic to their environment. To maintain water balance they must:

A) drink water to enable cells to lose water to the digestive tract
B) excrete large amounts of dilute urine
C) pump ions out through gill membranes
D) decrease free glucose to reduce osmosis

[darkz]

Hey guys! How do you solve this question ? - apparently the answer is B yet I don’t don’t understand why.

Fresh water fish have tissue that is hypertonic to their environment. To maintain water balance they must:

A) drink water to enable cells to lose water to the digestive tract
B) excrete large amounts of dilute urine
C) pump ions out through gill membranes
D) decrease free glucose to reduce osmosis

Because the fishes tissue is hypertonic, therefore it has a higher solute concentration than the surrounding water
 Therefore, water via osmosis goes from a low - high solute concentration, therefore in order to maintain water balance, they need to get rid of water. Hence b - dilute urine

[PhoenixxFire]

A bio question about fish! My speciality haha

So, the fish is hypertonic to its environment. That means that water moves into the fish through osmosis. The fish now has lots of extra water that it needs to get rid of.

A). Drinking water is not going to get rid of water
B). Excreting dilute urine will get rid of water.
C) & D) Neither of these would get rid of the excess water, at best they would just reduce the concentration gradient and therefore slow osmosis slightly - the fish still has heaps of extra water.

Edit: Damn it darkdzn, at least let me answer the fish question