CCNA and subnetting questions

[Seth Wilson]

Hello everybody,   Well, I'm taking a stab at the CCNA this Monday.  I'm wondering if, for the purposes of the exam, that when you get subnetting questions whether you're supposed to assume that subnet-zero has been enabled or not.  I just recently completed my MCSE, and with all the Microsoft tests the zero subnets cannot be used.  But I've seen it both ways in studying for the CCNA.  Thanks in advance.   ~Seth~