Question

In a lake with three trophic levels (non-native fish, zooplankton, algae), an algal bloom occurs when the small population of zooplankton declines due to the predation of the invasive fish. Which of the following describes why zooplankton are the keystone species in this scenario?

Zooplankton are the smallest of all the herbivorous marine mammals in their communities.
The small population of zooplankton have an unequal effect on the marine community.
Marine mammals depend upon the work of zooplankton to convert sunlight into food.
Zooplankton help other populations survive by keeping out other herbivores.

Answer 1

Zooplankton help other populations survive by keeping out other herbivores

Step-by-step explanation:

This is because a keystone species are species that have large effect on the the habitat and through its effect they help to keep the ecosystem in existence. They make sure that the ecosystem exist. They help populations survive by keeping out herbivores and feeding on the algae. They help drive nutrients cycle and transfer energy from algae to invasive fish.