Which part of the brainstem is responsible for controlling biological functions such as breathing?

The brainstem plays a crucial role in controlling fundamental biological functions vital for survival, including breathing, heart rate, and blood pressure. It consists of three main parts: the midbrain, pons, and medulla oblongata. The medulla oblongata, in particular, is directly responsible for autonomic functions such as breathing, as it contains centers that initiate and regulate the rhythm of respiration.

While the hindbrain, which includes the medulla, pons, and cerebellum, also contributes to these functions, referring specifically to the brainstem captures the entire structure responsible for vital functions. The midbrain and forebrain, while important for various cognitive and sensory processes, do not primarily control these involuntary biological functions like the brainstem does. Therefore, identifying the brainstem as the correct answer emphasizes its central role in managing essential life-sustaining processes.