Which structure in the brain controls heartbeat and breathing?

The medulla oblongata is the correct answer because it is a vital part of the brainstem involved in autonomic functions, specifically regulating essential life-sustaining processes such as heartbeat and breathing. The medulla controls the rhythmic contraction of the heart and the rate and depth of breathing by sending signals to the muscles involved in these processes.

This structure integrates information from the body and makes adjustments to maintain homeostasis, ensuring that the body functions effectively during rest and physical activity.

While the cerebellum is primarily responsible for coordination and balance, and the thalamus acts as a relay station for sensory information and is involved in regulating consciousness and sleep, the hypothalamus plays a crucial role in maintaining various homeostatic functions, such as hunger and temperature regulation, rather than directly controlling heartbeat and breathing. Thus, the medulla is uniquely positioned as the center for these critical autonomic functions.