Answer:
B. the cracks between the bumps on the brain.
Explanation:
Sulci also referred to as fissures, are the grooves which appear like cracks that is found in between an elevated ridge-like structure that looks like bumps, which are found on the surface of the cerebral cortex. The sulci that separate the cerebral cortex forming bumps, and making the cerebral cortex to form folds that are seen on the surface of the brain. The sulci by forming these folds help in increasing the surface area of the cerebral cortex that is made up of nerve cells and dendrites.
