Jalen observes a pond ecosystem near his home and records the changes he observes over a season for his science project. Ecosystems have important value for the organisms within them.

Which of the following determines whether an ecosystem is healthy? Choose the two that apply.

A.
a food chain with several members

B.
the number of organisms in an area

C.
the variety of species in an area

D.
many natural resources

the dark variety, as they are not visible on the dark tree barks

explanation:

evidence and logical support is essential for a scientist to do in order to maintain credibility. this is because no one can believe without any logic and without any evidence.hence a scientist can maintain credibility by proving himself and by answering logically so experiments prove very beneficial. logical hypothesis give conclusion which is acceptable. therefore, there are two main factors to maintain credibility by a scientist is evidence and logical support.