Physics=45ques. and each question carries 4 marks.

Chemistry=45 questions. same, each question carrying 4 marks

Biology=90 questions. same.

So weightage of Biology is very high and you have to focus on it a little more.

Now coming to the generalization which most of the students do like 45 ques form Botany and 45 form Zoology. Less from 11th and more from 12th.

So, please don't fall into that trap, keep working hard on all the parts.