Are the a levels above the ones you are doing?
If i remember correctly, aqa a level biology has a big essay on paper 3 im not sure about the other exam boards.
You can talk about that on your personal statements. There a lot of top business unis that dont ask for a humanity like the university of Warwick. A few of them do but im pretty sure that there are quite a few decent ones that dont. Search the complete uni guide business and all the top business courses will come up. Go through their entry requirements and you should find one that is suitable.