Do colleges look at your senior year?

1 year of a biological science is required to graduate high school, but I’m going to be a junior next year and I still haven’t taken a biology class. I was planning to take AP Bio senior year, but I was wondering if colleges will be able to see that I’m taking a biology class senior year. I heard that colleges decide whether they want you or not during around 1st semester of senior year, so during 2nd semester you are probably accepted into a college already. Is this really true? Will I be able to get into a selective college if I take my required year of biology senior year? Thanks in advance!

Depends on where you’re applying and if you’re applying EA/ED. A lot of admissions results don’t come out until March or so.

Also, I didn’t take the required chemistry class until senior year (I took AP Chem), and I’m at MIT now. So the answer to your last question is yes.