When you take water from tank A then tank A salinity would not be less or higher so option A and B are out. The answer is depends on the relative salinity of tank A to tank B.
Assuming the tank A salinity is higher than B, then the tank B salinity will also become higher.
Answer: <span>d.the salinity in Tank B would be higher</span>
Answer: Directional selection occurs when individuals with traits on one side of the mean in their population survive better or reproduce more than those on the other. ... Directional selection does the “heavy lifting” of evolution by tending to move the trait mean toward the optimum for the environment.
the answer is four hope this helps :)