Is 7A or 8A better for Chem Bio at Berkeley?

So im a chem bio major right now and am wondering if i should take the 8 or 7 series for physics. What i have heard is that the 7 series is harder and that the curves are low but the professor this semester is really easy (80% mean on the midterm) so i'm not sure. Never took AP physics in high school so yea. 8A is easier but then it has been said that the curve is higher so im not sure. any upperclman with any advice?