Rinderpest (a virus) has high mortality in wildebeest (a kind of herbivore), especially in young animals. From the early 1960s, after the elimination of a virus called rinderpest, the wildebeest population has increased dramatically from 1958 to 1978. The elimination of rinderpest impacted the wildebeest population. What type of factor is rinderpest

Answer:

density-dependent, top-down factor

Explanation:

In biology, limiting factors are resources and other conditions in the environment whose presence/availability limit the population growth rate. Density-dependent factors refer to the conditions whose effects on the size/growth of the population vary depending on the population density. Some examples of density-dependent factors include diseases, competition, and predation, etc. These factors can exhibit a positive or negative correlation with the population size. Moreover, bottom-up population control (species limitation by resources) refers to limitations placed by resources allowing growth (e.g.,  food source or habitat), while top-down population control (limitation by enemies), refers to limitations placed by factors that control the death rate in the population (e.g., predation or diseases).

Phenylketonuria causes a severe cognitive disability due to the inability to metabolize phenylalanine. It is an autosomal recessive disorder. About one in 12,000 newborns in Massachusetts are afflicted with the disease, skewed higher than the general US population due to more Irish-Americans. Assuming the gene is in Hardy-Weinberg equilibrium, the frequency of the carriers (heterozygotes) in Massachusetts would be calculated to be...