How Can Marine Animals Such as Sharks Live in Salt

Multiple Choice

How can marine animals such as sharks live in salt water?

A) They increase or decrease the amount of urea in their blood until the blood is isotonic with the environment.
B) They increase the amount of urea in their blood until the blood is hypertonic with the environment.
C) They decrease the amount of urea in their blood until the blood is hypotonic with the environment.
D) They contain impermeable membranes which do not allow the salt water to cross into their cells.
E) They block the movement of salt into their cells and maintain a constant blood salt concentration.