Question

Saltwater fish constantly drink water but still excrete concentrated urine to compensate for the water loss. They also have gills to help excrete excess salts. Conversely, freshwater fish absorb salt from their surroundings using their gills and their bodies reabsorb salt from their urine. This describes how salt- and freshwater fish _______.
a.
use their gills to drink
b.
keep the salinity levels even in their aquatic environments
c.
have adapted to deal with osmosis
d.
have evolved behavior patterns to match their physiology

Answer 1

c. have adapted to deal with osmosis

Explanation: The described differences in drinking, urine concentration, and gill function are osmoregulatory adaptations that allow fish to maintain internal salt and water balance despite differing external salinities.