Major

I am unsure if I should apply as a Biology major or undecided. I am worried there are too many potential biology majors, but I am also worried undecided will make me not be taken seriously.

If you’re interested in Biology, put Bio. Better to be upfront with them. Although, no matter what you put on your major, you’re going to applying as “LSA-undecided” as you don’t declare a major 'til sophomore year. You’re just putting what you’re interested in.
(I’m really glad I was just googling this ^^)