Hello Vicky

The subsidiary subject selection depends on the choices given to you. As you're doing/ want to do zoology hons then you have to choose 2 other subjects along with the language subject by side. Well.. mostly botany, chemistry, biotechnology, microbiology, physics, maths, .. are the available choices. Make sure you select those subjects which will help you in further studies or are relatable with your main subject ( zoology). As per me Botany and biotechnology/microbiology will be helpful.
The rest depends on your choice/interest for the subject. Make the selection in such a way that the other 2 subjects which you select doesn't become  burden on you. Hope you're getting my point.!

Good Luck.!