Why do scientists consider many factors when assigning an organism to a species?

The reason why is a few things, first, they have to make sure that the organism is related, and that they can see that. They don't wanna assign a bird as an insect on accident, so they do tests and then determine. Second, the more factors the better, if you consider all the species in the world, and what makes them different from eachother you would have a very long list. And that is it.
I hope this helps. If you need clarity or anything just ask.

Writing, you can revisit previous parts of the lesson by returning to the course map. be sure to refer to the lab’s student guide, which you can find on the first page of the lab experiment activity