What are the hard parts of AP Biology and AP Calculus AB
“Hard” isn’t black and white, concepts some find easy may be concepts others find difficult. Unless you mean something else, considering how vaguely worded this post was.
AB is a cakewalk. Hard parts might be later into the year when you get into more complex integration concepts, but if you do even a rudimentary preview of this over the summer it’ll be easy. BC wrecked me.