Assertion :- The development & differentiation of embryo into adult organism are the result of coordinated regulation of expression of several sets or genes.
Reason : The expression of all genes are not required simultaneously during development of organism.

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 and reason question, we will analyze both the assertion and the reason step by step.

### Step 1: Analyze the Assertion
**Assertion:** The development and differentiation of the embryo into an adult organism are the result of coordinated regulation of expression of several sets of genes.

- **Explanation:** This statement is true. The process of development from an embryo to an adult organism involves various stages where different sets of genes are activated or deactivated in a coordinated manner. This regulation is crucial for proper growth and differentiation of cells into various tissues and organs.

### Step 2: Analyze the Reason
**Reason:** The expression of all genes is not required simultaneously during the development of an organism.

- **Explanation:** This statement is also true. During the development of an organism, not all genes need to be expressed at the same time. Different genes are expressed at specific stages of development, which ensures that the organism develops correctly. For example, certain genes related to puberty will only be expressed at a certain age, while others may be active during earlier stages of development.

### Step 3: Determine the Relationship Between Assertion and Reason
- The reason provided explains why the assertion is true. The coordinated regulation of gene expression means that only certain genes are expressed at specific times, which aligns with the assertion that development is a regulated process.

### Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion. Therefore, the correct answer is:

**Option A:** Both assertion and reason are true, and reason is the correct explanation of assertion.

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