Final answer:
A shallow groove on the cerebral cortex is called a sulcus, while a deep groove is known as a fissure. Sulci serve as key landmarks for the brain's functional mapping.
Step-by-step explanation:
A shallow groove on the surface of the cerebral cortex is called a sulcus. The cerebral cortex, the outer part of the brain, is made up of hills called gyri (singular: gyrus) and valleys called sulci (singular: sulcus), which are essential in dividing the brain into functional centers. Whereas a deeper groove, such as the longitudinal fissure, is referred to as a fissure, which separates the brain into left and right hemispheres. Sulci are crucial in maximizing the amount of gray matter within the cranial cavity and are landmarks for mapping the brain into different functional regions or lobes.