Final answer:
The deep fissure that separates the two cerebral hemispheres is called the longitudinal fissure.
Step-by-step explanation:
The deep fissure that separates the two cerebral hemispheres is called the longitudinal fissure. This deep groove divides the brain into two halves or hemispheres: the left hemisphere and the right hemisphere. It is the most prominent sulcus on the surface of the brain.