Which of the following group is formed of only the hermaphordite organisms?

Options

A. a) Earthworm, tapeworm, housefly, frog
B. b) Earthworm, tapeworm, sea horse, housefly
C. c) Earthworm, leech, sponge, roundworn
D. d) Earthworm, tapeworm, leech, sponge

Explanation

To determine which group is formed of only hermaphrodite organisms, we will analyze each option provided and identify the organisms that are hermaphrodites.

### Step-by-Step Solution:

1. **Understanding Hermaphroditism**:
- Hermaphrodite organisms possess both male and female reproductive organs within a single individual.

2. **Analyzing Option A**:
- **Earthworm**: Hermaphrodite (has both male and female reproductive organs).
- **Tapeworm**: Hermaphrodite (also has both reproductive organs).
- **Housefly**: Not a hermaphrodite (has distinct male and female).
- **Frog**: Not a hermaphrodite (has distinct male and female).
- **Conclusion**: Option A is incorrect because it includes housefly and frog which are not hermaphrodites.

3. **Analyzing Option B**:
- **Earthworm**: Hermaphrodite.
- **Tapeworm**: Hermaphrodite.
- **Seahorse**: Not a hermaphrodite (males carry fertilized eggs but are not hermaphrodites).
- **Housefly**: Not a hermaphrodite.
- **Conclusion**: Option B is incorrect due to the inclusion of seahorse and housefly.

4. **Analyzing Option C**:
- **Earthworm**: Hermaphrodite.
- **Leech**: Hermaphrodite.
- **Sponge**: Hermaphrodite (many species are hermaphroditic).
- **Roundworm**: Not a hermaphrodite (has distinct male and female).
- **Conclusion**: Option C is incorrect because roundworm is not hermaphrodite.

5. **Analyzing Option D**:
- **Earthworm**: Hermaphrodite.
- **Tapeworm**: Hermaphrodite.
- **Leech**: Hermaphrodite.
- **Sponge**: Hermaphrodite.
- **Conclusion**: All organisms listed in Option D are hermaphrodites, making this the correct option.

### Final Answer:
The correct option is **D**: Earthworm, Tapeworm, Leech, and Sponge - all of these are hermaphrodite organisms.