Yes , you can be selected . It all depends on your rank if you get a good rank , then you will surely be selected . You are eligible for the test as you need to get above the cut off which is calculated on the basis of PCM , a language and any optional course . If you have marks above the cut off , then you are eligible for the test.  Now you need to get a very high score . Moreover, since you don't know Biology , you can't do anything about it . So you should face it with all your might .