Final answer:
The example of density-dependent factor is ten hawks hunting for food in the same field, since greater population density increases competition for resources, leading to higher mortality rates or lower reproductive success.
Step-by-step explanation:
The correct answer to the question of which scenario is an example of a density-dependent factor is a) Ten hawks hunting for food in the same field. This is because density-dependent factors are influenced by the population density of the organisms involved. As the population density increases, so does the impact of density-dependent factors. In the case of multiple hawks hunting in the same field, the food resource would become scarce more quickly due to the increased competition among the hawks, this would ultimately lead to a higher mortality rate or reduced reproductive success among the hawks due to the limited food supply.
Density-dependent regulation involves biological factors like predation, inter- and intraspecific competition, accumulation of waste, and diseases. These factors lead to an increased mortality rate as the population density increases. Conversely, density-independent factors, such as natural disasters or climate change, affect populations regardless of their density. For example, a catastrophic volcanic eruption would impact all individuals in an area, no matter how many of them there were.