Answer:
The correct answer is - A. Half of a population of birds is killed in a forest fire.
Step-by-step explanation:
Density-dependent factors are the factors that have varied or different effects as per the population size. In other words, the factors that are not influenced by the density of the population is density-dependent factors. These factors include competition, disease, and predation.
This could have a positive or negative relation to the size of the population as they increase with the increase of population size. Natural disasters not include in it.