Which terms complete the sentence given below?

PreyPredatorsHosts are often keystone species because they limit the populations of preypredatorsparasites species.

Predators are the keystone species because they limit the population of prey.

Explanation:

Predators are those species which hunt for other animals to consume them as food and live. Where prey are those animals who are being hunted and killed by predators.

Keystone species are those species whose absence or removal from a ecosystem will greatly reduce the diversity from the ecosystem to a huge extent.

Now, if a predator like lion is eliminated from the ecosystem, then the prey like deer, goats etc in the ecosystem will live and reproduce at a very high rate, which will greatly increase the population density of these species. So the food for them will be killed at a very high rate, decreasing the plant varieties and population. So the overall diversity in the ecosystem will be highly reduced.

So the predators like lions, tigers, etc are the keystone species of an ecosystem.