Layers of fossils in pillars, the rock covering them is dated and we get an exact time of each layer.
Answer:
There are many things that can be considered as a limiting factor such as water supply, competition, habitat space et cetera.
These factors affects the carrying capacity of the given environment. The human beings, animals uses food, space and water as their basic need.
These can affect the population of the organism if any of given components are presented in a limited amount.
The example of limiting factor that is human being to control the carrying capacity is food, space and water.
Physical Change, although the answer is widely disputed.