Question

what are sulci and gyri

Answer 1

sulci is the depression and gyri is the elevated part. these form the foldings like structure of the brain

Answer 2

A gyrus is a ridge on the cerebral cortex. It is generally surrounded by one or more sulci. A sulcus (Latin: "furrow") is a depression or fissure in the surface of the brain. It surrounds the gyri, creating the characteristic appearance of the brain in humans and other large mammals.