An evolutionary biologist makes decisions about whether to consider three different populations of copepods separate species based on observations of the individuals with which these copepods will mate. all combinations of these populations are able to mate with one another, but none of the combinations produce viable offspring. this biologist is most likely employing the species concept, and based on the application of this species concept to these results, there are most likely species of copepods present.

1. Biological

2. Three

Explanation:

The biological species concept is based on the reproductive isolation of species from each other. According to the biological species concept, when members of one or more populations are able to interbreed with each other to produce viable and fertile progeny, the populations belong to the same species. Members of different species cannot interbreed. Members of two species may be able to interbreed but cannot produce the fertile and viable progeny due to post-reproductive isolation mechanisms.

According to the given information, members of three populations of copepods are not able to produce viable offspring by interbreeding with each other. This means that according to the biological species concept, three populations are three different species.