I’m a rising senior and I have yet to take any SAT subject tests. Honestly, I didn’t really know much about them until a few months ago.
I’m planning to take Math 2 and one science (I’m planning to be pre-med, major in either cognitive science or biology). These SAT IIs are really only necessary for the prestigious schools I’m going to take a shot at: Tufts, UCLA, Cornell, etc. All my safeties will not even take or look at the scores.
I have background in all three subjects. I took Chem H (freshman year) and the IB Chem HL 1 (last year, first semester). I took Bio H (sophomore year) and IB Bio HL 1 (last year, second semester, and I’m taking HL 2 this coming year). And I took AP Physics 1 last year (received a 4 on the AP test).
I probably feel the least comfortable with Physics. I missed a lot of class and never felt comfortable again in the material, unfortunately. I’m rather surprised I didn’t get a 2 or 3 on the AP test!
So, in your guys’ opinion, should I take Chem or Bio E or Bio M? I don’t know how much time I can put into studying, but I’m assuming I should do enough to get a 750+. I just need to know which subject of review book to buy, so I can start reviewing the material and prepare for the November test. Thanks! 
Does any of the colleges you will apply to require to take a specific SAT subject test besides math?
If not then you can take either chem or bio. AP Physics 1 does not cover enough materials for SAT Physics.
UCLA requires 2 SAT subject tests: Math 2 and a subject closely related to your intended major. You should take bio if you want to major in bio.
https://www.admission.ucla.edu/prospect/Adm_fr/fracadrq.htm
@coolweather Thanks for your response! UCLA only requires subject tests for engineering majors, according to the link.
None of the UC’s are allowed to require Subject Tests. UCLA only “encourages” Subject Tests for engineering. Sounds like your biology is far more current. You can take one of the Official SAT Subject Tests to verify.
Yep, usually “Recommended” for competitive majors
Pick the one you would do the best in.
Physics is ridiculous; unless you absolutely love physics and know everything from AP Physics 2, do not take it (as others have said).
In my opinion, Chemistry is MUCH easier to get an 800 in compared to Biology. Chemistry isn’t as theoretically challenging as Physics, and the curve is more generous than Biology (especially Biology E). However, if you do love Biology, I would definitely recommend Biology (although keep in mind that you must answer almost all of the questions correctly in E and most of the questions correctly in M to receive an 800). Chemistry allows you to miss ~3.
If you are excellent in both subjects and/or you are amazing at chemistry, I would pick Chemistry.
If you seriously love Biology and excel in it, I would pick Bio-M.
Only pick Bio-E if you are confident in getting only ~1 wrong and you enjoy ecology/environmental science.