This is not a puzzle, and your answer is not a solution. It's formally wrong in terms of actual biology. Another way to think of it is as a narrative that attempts to explain- but it isn't a particularly useful one. It's not a "right/wrong" (and it's not something people can "figure out").

That some members of a population are sterile doesn't require you to completely rearrange your definition of biology, speceis, and organism.