Which of the following best explains how a biotic factor can control the population of a species in an ecosystem?
a sudden drop in temperature may cause many individuals in a population to die.
competition between two species may force one of them to migrate to survive.
disease may lead to a decline in the reproductive rate of the species’ main predator.
lack of water during a drought may cause many of the individuals in a population to die.

The most appropriate answer would be Competition between two species may force one of them to migrate to survive.

Competition is a type of biological interaction in which organisms of same or different species compete for similar resources essential for their survival in an ecosystem.

Organisms can compete for limiting sources (such as air, water, food), territory, and mating rights.

In inter-species competition, species with the slightest advantage will grow and result in the migration or extinction of other species in that ecosystem.

Thus, the population of other species would decrease or extinct in that ecosystem.

For example, lion and cheetah may compete for their common prey that is, deer.

B): Competition between two species may force one of them to migrate to survive.

Explanation:

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.