The answer is b. Hope this helps :)
Differentiation->Fertilization->Gamete Production-Mitosis
<span>Fertilization->Differentiation->Gamete Production->Mitosis </span>
<span>Gamete Production->Fertilization->Mitosis->Diff... </span>
<span>Mitosis->Fertilization->Gamete Production->Differentiation </span>
<span>The bottleneck effect is the cause of the sudden shift in the genetic information of the population. Due to the landslide, suddenly high number of the members of the main population died, and this caused genetic drift for reducing the variation in the existing generation, which is now widely different from the original one.</span><span />
Sea snails help to keep the algae's population from growing to high. And the algae provides the sea snails with energy from the snails eating it as a food source.