Need clarity on Science courses and labs.

I need to fulfill B1, B2, & B3. From my understanding you need to take at least one lab class to fulfill B3. Does the lab have to be corresponding with B1 or B2 and does it have to be with the same professor? For example, if I decide that I want to take ANTH 300, do I need to also enroll for the lab that has the same professor?