Animals with cleidoic eggs show

Options

A. External fertilization, internal development
B. Internal fertilization internal development
C. External fertilization, external development
D. Internal fertilization external development.

Answer

**Step-by-Step Solution:**

1. **Understanding Cleidoic Eggs**: Cleidoic eggs are a type of egg that is enclosed in a protective shell. This shell allows the embryo to develop in a controlled environment, isolating it from the external environment.

2. **Fertilization Types**: There are two main types of fertilization:
- **External Fertilization**: This occurs outside the female's body, common in aquatic animals where eggs and sperm are released into the water.
- **Internal Fertilization**: This occurs inside the female's body, where the sperm fertilizes the egg.

3. **Development Types**: Development can also be categorized into:
- **External Development**: The embryo develops outside the mother’s body, typically in an egg.
- **Internal Development**: The embryo develops inside the mother’s body.

4. **Characteristics of Cleidoic Eggs**: Animals that produce cleidoic eggs typically have adapted to terrestrial environments. The shell of the cleidoic egg prevents desiccation (drying out) and allows for the embryo to develop in a stable environment.

5. **Fertilization and Development in Cleidoic Egg Laying Animals**:
- Animals that lay cleidoic eggs (like reptiles and birds) generally undergo **internal fertilization**. This means that the sperm fertilizes the egg inside the female's body.
- After fertilization, these animals lay their eggs in an external environment, where the development of the embryo occurs outside the mother’s body. Thus, they exhibit **external development**.

6. **Conclusion**: Therefore, animals with cleidoic eggs show **internal fertilization and external development**.

**Final Answer**: Option D - Internal fertilization and external development.

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