Assertion : Cleavage in human zygote is holoblastic .
Reason : Its egg contain enormous quantity of yolk.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion .
B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is False .
D. If both Assertion & Reason are False.

Answer

To solve the assertion-reason question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that "cleavage in human zygote is holoblastic."
- Holoblastic cleavage refers to a type of cleavage where the entire egg is divided into smaller cells (blastomeres). In humans, the cleavage is indeed holoblastic, meaning that the zygote divides completely into smaller cells.

### Step 2: Understand the Reason
The reason states that "its egg contains an enormous quantity of yolk."
- In humans, the amount of yolk in the egg is moderate, not enormous. The presence of yolk affects the type of cleavage; eggs with a large amount of yolk typically undergo meroblastic cleavage, where only part of the egg divides. Since human eggs have a moderate amount of yolk, this statement is incorrect.

### Step 3: Evaluate the Truth of the Assertion and Reason
- The assertion is true: cleavage in the human zygote is indeed holoblastic.
- The reason is false: the human egg does not contain an enormous quantity of yolk.

### Step 4: Determine the Correct Option
Based on the evaluation:
- Option A: Both assertion and reason are true and reason is a correct explanation of the assertion. (False)
- Option B: Both assertion and reason are true but the reason is not a correct explanation of the assertion. (False)
- Option C: Assertion is true but the reason is false. (True)
- Option D: Both assertion and reason are false. (False)

Thus, the correct answer is **Option C**: Assertion is true but the reason is false.