Breathing rate in mammals is controlled by a part of the brain called :

Options

A. hypothalamus
B. medulla oblongata
C. cerebellum
D. cerebrum

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which part of the brain controls the breathing rate in mammals.

2. **Identifying the Respiratory System**: Breathing in mammals is facilitated by the respiratory system, primarily using lungs located in the thoracic cavity. The main function of this system is to facilitate gaseous exchange—taking in oxygen and expelling carbon dioxide.

3. **Role of the Nervous System**: The breathing process is regulated by the nervous system. The rate of breathing must adjust according to the concentration of gases in the body, particularly oxygen and carbon dioxide.

4. **Chemosensitive Areas**: There are chemosensitive areas in the brain that detect changes in the concentration of carbon dioxide and hydrogen ions (H+). When the concentration of carbon dioxide increases, these areas signal the need for adjustments in breathing.

5. **Respiratory Rhythm Center**: The respiratory rhythm center, which is responsible for controlling the rate of breathing, is located in the medulla oblongata of the brain. This center activates when there are changes in the concentrations of carbon dioxide and H+ ions, ensuring that breathing is adjusted accordingly.

6. **Conclusion**: Therefore, the part of the brain that controls the breathing rate in mammals is the **medulla oblongata**.

**Final Answer**: Medulla oblongata.

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