In frogs, heart-beat is controlled by

Options

A. Cerebellum
B. Spinal cord
C. Medulla oblongata
D. Mid-brain.

Explanation

**Step-by-Step Solution:**

1. **Understanding Heartbeat Control**: The heartbeat in frogs, like in many animals, is controlled by two primary systems: the endocrine system and the nervous system.

2. **Identifying the Systems**: The nervous system can be further divided into the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). The CNS includes the brain and spinal cord.

3. **Brain Structure**: The brain is divided into three main parts: the forebrain, midbrain, and hindbrain. Each part has specific functions and controls various involuntary processes.

4. **Focus on the Hindbrain**: The hindbrain consists of structures such as the cerebellum, pons, and medulla oblongata. The medulla oblongata is particularly important for controlling involuntary functions, including heartbeat.

5. **Involuntary Processes**: Heartbeat is an involuntary process, meaning it is not consciously controlled. This function is primarily regulated by the medulla oblongata.

6. **Conclusion**: Therefore, in frogs, the heartbeat is controlled by the medulla oblongata, which is part of the hindbrain.

**Final Answer**: The heartbeat in frogs is controlled by the medulla oblongata.

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