I want to apply to top schools and am interested in bio major but don't know if I should write my essay about bio or not

In your essay definitely talk about why your interested in biology and what led you to choosing that as your major. When college look at your profile they should understand why you want to study biology and how you have supported your interests in that field. Your extracurriculars should also back that up. So talk about how your academics and extracurriculars have influenced you and caused you to major in biology. As a result, it is not recommended that you apply for a different major and switch to biology. Cause then you will be writing about a major that you have no interest in studying and is not supported by your academics and extracurriculars.

If you are asked to write more about your academic life and the course you want to study when admitted, I'll say you focus more on biology major and do not try yourself for another major...." Focus on your set course " which is bio major.

Hope this was helpful.

Best of luck.

Admissions officers would get super bored if all they read were essays about applicants' interests in their desired major, therefore I would not recommend writing about that as a matter of course. I would write about your interest in studying biology only if you have something personal, unique and genuinely interesting to say about it. Your starting for your personal essay should be to describe something distinctive and authentic about yourself, ideally in a way that is fresh and new to the admissions reader. It might be that you have the ability to write an essay like this about your interest in biology - but, it might not. If the latter, I would choose something else.