How are changes in populations related to the availability of an ecosystem's resources?

a.
changes in population are independent of the availability of an ecosystem's resources.
b.
large populations need the same amount of resources as small populations.
c.
population sizes are limited by the amount of resources that are available.
d.
as populations grow, ecosystems produce more resources in order to support the larger population.

The population sizes are limited by the amount of resources that are available relates the changes in populations are related to the availability of an ecosystem's resources.

C.  Population sizes are limited by the amount of resources that are available.

Explanation:

Population regulation is a phenomenon in which the population of a species utilizing the same resources meets the limiting factors. These limiting factors limit their growth and size.

The limiting factors can be density-dependent or density-independent limiting factors. The density-dependent limiting factors cause reduction in per capita growth of a population when the size of the population living in an area grows larger than the source of food available in that area.  

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?