Answer:
Predator prey
Step-by-step explanation:
Animals that feed on other animals are called predators and the animals they eat are called prey. All predators have specific interactions with their prey as they are locked in an evolutionary "arms race". The prey will try to develop novel traits to survive as the predators will try to adapt to these. This is not a conscious process, but rather an evolutionary one, where prey individuals that have a survival advantage will survive and thus reproduce more.
The second image illustrates a predator-prey cycle where an increase in the prey numbers will lead to an increase in the predator numbers. This in turn will lead to a decrease in the prey number which in turn will also lead to a decrease in the predator's numbers.
The third image is a trophic or ecological pyramid in which X are the primary producers (ex. plants), Y are the animals that feed on these (prey) and Z are the predators that feed on Y. In general, top predators are not hunted and eaten by other species which is why they are at the top of the pyramid.