It depends on the sixthform or college you go to, for mine we are required to have at least a 6 in maths but as the person above said A level biology doesn’t actually require much maths skills just a basic understanding of it and when you do learn something particularly maths-y like standard deviation they will teach you how to do it so you will be fine trust me as long as the school you would like to go to is okay with it, however looking further into the future, some universities do look at gcse maths grades and would like 7s/8s but again this is only a select few so you should be okay just make sure to check where you’re applying
good luck!