Hello there!

Greetings!

If you are asking about best you tube channel for class 11 biology then I will suggest you to go with exam fear and shiksha house,  these two are the best channels when it comes to biology,  animation in these channels helps to understand concepts well.  When it comes to chemistry,  you should follow Arvind Arora sir , he is a great tutor and will help you to understand concepts well.

Thankyou

Good luck