Fertilization is internal in

Options

A. Toads
B. Frogs
C. Dog fish
D. Cat fish

Answer

To solve the question "Fertilization is internal in", we will analyze the options provided and determine which organism exhibits internal fertilization.

### Step-by-Step Solution:

1. **Understanding Fertilization Types**:
- Fertilization can be classified into two main types: internal and external.
- **Internal Fertilization**: This occurs when the fusion of male and female gametes (sperm and ovum) takes place inside the female's body.
- **External Fertilization**: This occurs when the gametes fuse outside the body, typically in a watery environment.

2. **Analyzing the Options**:
- **Toads**: Toads are amphibians that typically exhibit external fertilization. The male and female toads release their gametes into the water during mating.
- **Frogs**: Similar to toads, frogs also undergo external fertilization. They engage in a process called amplexus, where the male fertilizes the eggs as they are laid in water.
- **Dogfish**: Dogfish, which are a type of shark, exhibit internal fertilization. The male dogfish has a specialized organ called a clasper that allows it to transfer sperm directly into the female's body.
- **Catfish**: Catfish, like the clarius species, also undergo external fertilization. The female lays eggs in a nest, and the male fertilizes them externally.

3. **Identifying the Correct Answer**:
- Based on the analysis, the only organism from the options that exhibits internal fertilization is the **Dogfish**.

### Final Answer:
Fertilization is internal in **Dogfish**.

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