Why is the cerebral cortex folded?

1. The cranial cavity is a limited space. 2. Folding buys surface area. 3. Extensive folding in the cerebral cortex enables more gray matter to fit into this limited space. 4. So the answer is to fit more gray matter. _Source: OpenStax 'Anatomy and Physiology 2e', Ch 13 'Anatomy of the Nervous System'_