C. Convection.
That is the process you are describing.
The mechanism responsible for the changes in fish size between generation 1 and generation 100 is the gene flow mechanism.
<h3>What is the gene flow mechanism?</h3>
Individuals may migrate from one group or region to another as part of another evolutionary mechanism. Interbreeding between the migrant individuals and the new population adds their genes to the local population's gene pool. The population's gene flow is established as a result.
For instance, when wind takes seeds far outside the range of the parent plant population, gene flow occurs. Another illustration might be when animals leave a herd. They are compelled to migrate as a result, adding new genes to the gene pool. Because gene flow makes gene pools more similar to one another, it tends to increase the similarity between remaining populations of the same species.
Learn more about genes with the help of the given link:
brainly.com/question/1480756
#SPJ4
Answer:
Glucose Storage in plants
