Hello Dhivya R,

Well, irrespective of your subjects, you can apply for KVPY exam, as per the exam's eligibility is as follow:

Stream SX: Students enrolled in XII Standard/ (+2) (Science subjects) during the academic year 2020–21 and aspiring to join undergraduate program in Basic Sciences namely Physics/Chemistry/Mathematics & Biology leading to  B.Sc./B.S./B.Stat./B.Math./Int. M.Sc./Int. M.S. for the session 2021–22 provided they have secured a minimum of 75% (65% for SC/ST/PWD) marks in aggregate in MATHEMATICS and SCIENCE subjects (Physics/Chemistry/ Biology) in the X Standard Board Examination during the academic year 2018-19 are eligible to appear for the Aptitude test.

You can refer to ( KVPY official site (http://kvpy.iisc.ernet.in/main/eligibility.htm) )

But, for qualifying exams with good marks, you need to prepare yourself for Biology too!, but Biology isn't necessarily should be your subject....

Hope this helps, and feel free to ask any further query...