What is the main function of the cerebellum in the brain?

The cerebellum's primary role is to coordinate voluntary movements and maintain balance and posture by processing sensory information from various parts of the body. It integrates input from the sensory systems, the spinal cord, and other parts of the brain to fine-tune motor activity. This helps ensure smooth, coordinated movements and allows for adjustments based on sensory feedback.

In contrast, thought processing is mainly handled by the cerebral cortex. Regulation of breathing is controlled by the brainstem, particularly the medulla and pons, which manage autonomic functions. The conduction of nerve impulses is a function of neurons and is not specific to one brain region but rather a general property of the nervous system. Therefore, the coordination of sensory input is the best answer, as the cerebellum plays a key role in integrating this information to facilitate coordinated movement.