Why is this passage an example of indirect
characterization?

It's to know your purpose before you read something because a purpose can:

Before ending this lesson, take a moment to review an informative research essay you have written. you’ve probably already written a conclusion to the essay. but is it the best conclusion it can be? does it properly summarize the main subtopics of your essay? does it state in one or two sentences the “so what” of your topic. if your topic was abraham lincoln, your essay shouldn’t be just about abraham lincoln. it should answer, “so what about abraham lincoln? ” take five or ten minutes, and looking only at that single paragraph, revise your conclusion

Which revision, if any, best fixes the bolded (capitalized in this case) part of the sentence? female cardinals, a somewhat drab bird compared to the males, blend in well with their environment. no change somewhat drab birds a somewhat drab's bird somewhat drab bird's