What do i write here?

Would really appreciate it, i have an idea but not completely sure

Aphids are tiny insects that feed on plants. ladybugs are to plants because they eat aphids. which type of organism are aphids in this scenario? co decomposers predators prey producers

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important