Question

Many fresh water animals cannot live for long in sea water and vice versa mainly because;

• A. Change in nitrogen level
• B. Change in thermal tolerance
• C. Variation in light intensity
• D. Osmotic problems

Answer 1

The correct option is D Osmotic problems

In freshwater a fish is hypertonic to its environment, it means fish is saltier and water continuously moves into the fishes body via Osmosis. When freshwater fish is placed in salt water the freshwater fish is hypotonic or less salty when compared to the environment. This means water continuously moves out of the fish body and lead to the death of the fish. Hence Many freshwater animals cannot live for long in sea water and vice versa mainly because of Osmotic problems.

So the correct answer is 'Osmotic problems'.