Some people are naturally better in Phy, or Bio. It just
depends. I'm taking Bio and it's not really that hard (I would
literally DIE if I take Phy), if you're really interested in Bio,
then you will find it easier than Phy.
Bio is more of memorising, Phy is more of calculations. I'm not
really sure since I don't take Phy, but well, anyway, for
humanities. I'm taking Hist/SS.
I mean, I find that it's btr for me to take Hist than Geog,
since I totally hate Geog. Then again, it's your interest area you
should consider. But some of my friends say that Geog is easy. I
like Hist because first, well, I like History lol. Second, by doing
Hist you would also learn, and practice Source-Based qns, which are
also required in SS. It's just like you are killing 2 stone with
one bird.