Assertion. Cerebellum is large, lobed and convoluated in active animals.
Reason. Cerebellum coordinates voluntary movements and helps maintain posture and equilibrium

Options

A. If both A and R are true and R is the correct explanation of A.
B. If both A and R are true and R is not the correct explanation of A.
C. If A is true but R is false.
D. If both A and R are false.

Answer

To analyze the given assertion and reason, we will follow these steps:

### Step 1: Understand the Assertion
The assertion states that "Cerebellum is large, lobed and convoluted in active animals."
- The cerebellum is indeed a significant part of the brain located in the hindbrain. It is larger in active animals because they require more coordination for movement and balance.
- The cerebellum has a lobed structure, typically consisting of two hemispheres and a central lobe known as the vermis.
- The convoluted nature refers to the grooves and ridges on its surface, known as the cerebellar cortex.

### Step 2: Understand the Reason
The reason states that "Cerebellum coordinates voluntary movements and helps maintain posture and equilibrium."
- This statement is true as well. The cerebellum plays a crucial role in coordinating voluntary movements, which are movements that we can control consciously.
- It also helps maintain posture and balance, which are essential for an organism’s stability and movement.

### Step 3: Evaluate the Relationship Between Assertion and Reason
- The assertion is true, and the reason is also true.
- Furthermore, the reason provides an explanation for the assertion. The size and complexity of the cerebellum in active animals are directly related to its functions of coordination and balance.

### Conclusion
Both the assertion and the reason are correct, and the reason accurately explains the assertion. Therefore, the correct answer is that both statements are true, and the reason correctly explains the assertion.