Since you will probably want a job once you get out of college, you consider which schools have a good reputation in biology. That is one way of signalling. Ideally, you want a school that signals strong for biology but not for other majors: that way you don't get the increased competition against students in other areas.

Other considerations can be important to factor in as well, but others have already mentioned these.

You've implied that you are not from the US. I have noticed that students who have peers of a similar nationality often have an easier time assimilating into universities and seem to form stronger connections both with other international students and with local students. If I would have to guess, it is because they don't end up feeling as displaced. So you may want to consider which schools are likely to get more transfers from your country or have strong international programs in general.