hi mak. as for as zoology is concerned i will suggest you to consult various books for various topics to prepare.i.e for topics related to genetics Girton is best ...we must have to opt smart strategy to prepare zoology. the strategy which i am talking about can be summerised as
clear your concept about specific topics
use specific books and net for this
focus on objectives also
memories
practice of diagrams.
it will defiantly help you...regards
ayesha