Answer:
A Mutations are sometimes helpful, sometimes harmful, and sometimes neutral.
Explanation:
I did the test.
It is useful for an ecologist to identify the keystone species in an ecosystem because the keystone species is important to maintaining the stability of an ecosystem, and any changes in the keystone species population shows that there is changes in ecosystem health.
Answer. They are the “last trophic level” in some hierarchies because they feed on everything (National Geographic). However, according to the strict trophic level definition they would be primary consumers.
