Hi Shirsendhu,

To download  previous year question paper of Biology for Class 11 you should follow these steps:-

• On smartphone Download the mycbseguide app.
• On desktop go to mycbseguide.com.
• Sign up in that using mobile number.
• Select class and subjects.
• Then go to biology section and you will see there previous years papers section.
• Tap on that section and you will get list of all the papers available.

You may refer to this article to get NCERT solutions of Class 11 Biology.

I hope this information helps you.

Good Luck!