The superficial blastula is the characteristic of

Options

A. Birds
B. Reptiles
C. Insects
D. Annelids.

Answer

To solve the question regarding the characteristic of the superficial blastula, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Term "Superficial Blastula":**
- The superficial blastula is a type of blastula formed as a result of superficial cleavage. This means that during the early stages of embryonic development, the cleavage occurs only at the surface of the yolk, leaving the yolk mass uncleaved.

2. **Identify Key Features of Superficial Blastula:**
- In a superficial blastula, the blastocele (the fluid-filled cavity) is absent.
- There is a single layer of blastomeres (cells) surrounding the uncleaved yolk.

3. **Analyze the Options:**
- a. Birds: Birds typically exhibit a different type of cleavage (discoidal cleavage) due to their large yolk.
- b. Reptiles: Similar to birds, reptiles also show discoidal cleavage.
- c. Insects: Insects are known to have superficial cleavage, leading to the formation of a superficial blastula.
- d. Invertebrates: This option is not relevant to the question.

4. **Conclusion:**
- Based on the characteristics of the superficial blastula and the types of cleavage in the options provided, the correct answer is **c. Insects**.

### Final Answer:
The superficial blastula is characteristic of **c. Insects**.

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