Assertion : Embryonic development proves interrelationship and common ancestory of metazoans.
Reason : It involves similar sequence of five dynamic processes during development

Options

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

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that embryonic development demonstrates the interrelationship and common ancestry of metazoans. Metazoans refer to multicellular organisms, primarily animals, that share a common evolutionary lineage.

2. **Explaining Embryonic Development:**
- Embryonic development involves the processes that occur from fertilization to the formation of a fully developed organism. This development is crucial in understanding how different species are related through common ancestry.

3. **Identifying the Reason:**
- The reason provided is that embryonic development involves a similar sequence of five dynamic processes. These processes are critical in establishing the similarities observed in the embryonic stages of different metazoans.

4. **Listing the Five Dynamic Processes:**
- The five dynamic processes involved in embryonic development are:
1. **Gametogenesis:** Formation of gametes (sperm and egg).
2. **Fertilization:** Fusion of gametes to form a zygote.
3. **Cleavage:** Rapid cell division of the zygote leading to the formation of a blastula.
4. **Gastrulation:** Rearrangement of the blastula cells to form a gastrula, which has different layers (ectoderm, mesoderm, endoderm).
5. **Organogenesis:** Development of organs from the germ layers formed during gastrulation.

5. **Connecting the Assertion and Reason:**
- The assertion and reason are linked because the similarity in embryonic development processes across different metazoans supports the idea of a common ancestry. The presence of similar structures, such as pharyngeal pouches and post-anal tails in various species, further illustrates this connection.

6. **Conclusion:**
- Both the assertion and reason are true, and the reason provides a correct explanation for the assertion. This indicates that embryonic development is a key factor in understanding evolutionary relationships among metazoans.