Question

A marine bony fish continuously

• A. Acquire water and get rid of salt
• B. Get rid of both water and salt
• C. Get rid of water and acquire salt
• D. Acquire both water and salt

Answer 1

The correct option is A Acquire water and get rid of salt

The main function of loop of Henle is the reabsorption of water from the contents of renal tubules. Fresh water fish has no loop of henle. Their bodies take on water by osmosis, therefore they rid their bodies of excess water rather than conserve it. Fresh water fish drink little water and produce large amount of urine. These mechanism work to maintain their body fluids hypertonic to their fresh water surroundings. That is, their body fluids contains more dissolved substances and have lower concentration of water than the water in which they live. Marine fish on the other hand lose water by osmosis to their environment. To compensate, they drink sea water and secrete the excess salts from their gills. Thus, option A is correct.