Marine fish can keep their internal environment hypertonic with respect to the surrounding salty water by retaining.

Question

Accepted Answer

Excessive urea which will increase their internal solute concentration and prevent body shrinkage in hypertonic environment. A is correct because marine fish use urea to raise their internal solute concentration, balancing the surrounding saltiness. B is incorrect because trimethyl alanine is not the primary mechanism for this osmotic balance. C is incorrect because ammonia is generally excreted and does not serve this purpose in marine fish osmoregulation. D is incorrect because trimethylamine oxide is not the substance responsible for maintaining hypertonicity in this manner.