Answer:
A density-dependent factor
Explanation:
A density-dependent factor is a factor that affects the density of a population and it varies according to the density of the population. The density of the dependent factor population depends on the availability of food, water, disease, migration and many more things that is related to the environmental factors but the main factor that affects the density of population is the availability of food. If the population of rabbit decrease due to the availability of flood, drought, and from other factor and have to migrate from one place to another place or start to die. If the rabbit population starts to reduce then the fox population also effects and these also start to migrate or die. So the life cycle effect all the population on earth.