In which of the following organisms self fertilization is seen?

Options

A. Sharks
B. Roundworm
C. Earthworm
D. Tapeworm

Answer

To determine which organism exhibits self-fertilization, we need to analyze the characteristics of each option provided. Here’s a step-by-step solution:

### Step 1: Understand Self-Fertilization
Self-fertilization is the process where an organism produces both male and female gametes and these gametes fuse within the same individual. This typically occurs in hermaphroditic organisms.

**Hint:** Self-fertilization involves the fusion of male and female gametes from the same organism.

### Step 2: Analyze the Options
1. **Shark**: Sharks are dioecious, meaning they have separate male and female individuals. Therefore, they cannot self-fertilize.
- **Hint:** Look for organisms with separate sexes to rule them out for self-fertilization.

2. **Roundworm**: Roundworms also exhibit separate sexes, with distinct male and female individuals. Thus, they do not self-fertilize.
- **Hint:** Separate sexes again indicate that self-fertilization is not possible.

3. **Earthworm**: Earthworms are hermaphrodites, possessing both male and female reproductive organs. However, they do not self-fertilize because their male and female organs do not mature simultaneously, preventing fertilization within the same individual.
- **Hint:** Hermaphrodites do not always self-fertilize; check for the timing of organ maturity.

4. **Tapeworm**: Tapeworms are also hermaphroditic and possess both male and female reproductive organs in each segment. They can self-fertilize because they can produce both types of gametes and fertilize their own eggs.
- **Hint:** Look for organisms that can produce both gametes and have the ability to fertilize them.

### Step 3: Conclusion
Based on the analysis, the organism that exhibits self-fertilization is the **tapeworm**. Therefore, the correct answer is option 4: **tapeworm**.

**Final Answer:** Tapeworm (Option 4)