The correct statement is: a) There are more prey species than predator species.
In most ecosystems, prey species outnumber predator species. This is because predators rely on prey for their survival, and a higher number of prey species ensures a stable food supply for predators. If there were too many predators compared to prey, the predators would quickly deplete their food source, leading to a collapse in the predator population.
Statement b) is incorrect because most predators do not have many natural predators. Predators are usually at the top of the food chain and have few or no natural enemies.
Statement c) is incorrect because the number of predator and prey species is not equal. As mentioned, prey species are more numerous.
Statement d) is incorrect because predators have a significant impact on an ecosystem. They help control the population of prey species, which in turn affects the vegetation and overall health of the ecosystem.