Dear aspirant

You haven't mentioned anything about which exam you want to know.

As your profile suggest you are medicine aspirant I hope so your enquiry is about the neet exam.

Here I'm providing a link below which will tell you chapterwise weightage in all three subject. Also it will tell the chapters which you must do before appearing on exam. As those particular chapters may give you good marks.

https://www.google.com/amp/s/medicine.careers360.com/articles/do-or-die-chapters-for-neet/amp

Hope this information helps you

All the best & perform well !!!