Some questions about Caltech

Hello!
I was wondering if I should take 3 SAT subject tests, looking at the EA/RD threads, it seems that a majority of accepted students have taken 3. Looking at the Caltech website, it says math II and a science ST is enough, but is there a preference for 3 subject tests?
Also, is it possible for students to get in without research? What percentage of accepted students have done research (it always seems to be molecular biology stem cell research isn’t it)? I’m an American citizen living in HK, and they don’t really do research opportunities here. Will Caltech take that into account?
Thanks a lot!

@SerenePotato Sorry, don’t know about their preference on the SAT IIs. Son took 2 tests and got 800s, so he didn’t take any more. So, he got in without taking 3.

He did research, but physics/astrophysics, not any sort of bio. I’m sure plenty of students get in without doing research because maybe they did something else.

Caltech does take into account what opportunities were available to potential students. So if there aren’t really research opportunities where you live, I recommend not worrying about it too much. Rather, take advantage of what opportunities are available.