Q3.19. Think about what the terms density-dependent and density-independent mean. Which of the following statements about how density-dependent and density-independent factors affect population growth is TRUE?

(A) The effect of most density-dependent factors on population growth is greater when population density is low.

(B) The effect of most density-dependent factors on population growth is greater when population density is high.

(C) The effect of most density-dependent factors on population growth is not related to population density.

(D) The effect of most density-independent factors on population growth is greater when population density is high

Answer: (B) The effect of most density-dependent factors on population growth is greater when population density is high.

Explanation:

A limiting factor is the one, which can limit the population of the species in an environment.

The density-dependent limiting factor is the one that exerts an effect on the population of the species depending upon its size or density.

Examples of the density-dependent limiting factor include predation, migration, disease, availability of the food, and others.

For example, if when the population of the species are densely populated, they can transmit the internal and external parasites to the host organisms through skin contact and by bodily secretions. The parasites will thrive in the densely packed host population. A reduction in the host population will reduce the incidences of infection of the host by the parasite. This will make the transmission of the parasite difficult.