HELP!

School registration is this month and there's so many options and not enough room to take all the classes I want to! I can't pick which ones I'd rather do... HELP!!!!!!
For science my options are:
1) biology
2) agricultural biology (which I'm not taking cause I'm not going to be a farmer)
or 3) chemistry
WHICH SHOULD I CHOOSE?
Then 3 of my electives are already set. Volleyball and 2 trimesters of seminary. Now I just need to pick 2 more. And I can't pick between two tri's of social dance where we get to learn fun dances like the waltz, line dancing, swing dancing, etc., or child developement (seeing as how I'm going to major in elementary edu.), or 2 tri's of choir! HELP!!!