Select the group of organisms given below those have disploblastic members only.

Options

A. Ctenoplana, Taenia , Fasciola
B. Euspongia , Physalia , Meandrina
C. Wuchereria, Culex, Limulus
D. Aedes, Ascaris, Hydra

Answer

To solve the question of identifying the group of organisms that have only diploblastic members, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Diploblastic Organisms**:
- Diploblastic organisms are those that develop from two embryonic layers: the ectoderm and the endoderm.

2. **Identify Relevant Phyla**:
- The main phyla that contain diploblastic organisms are:
- **Porifera** (sponges)
- **Cnidaria** (jellyfish, corals, sea anemones)
- **Ctenophora** (comb jellies)

3. **Evaluate the Options**:
- We need to analyze the given options to see which ones consist entirely of organisms from the diploblastic phyla.

4. **Option A**: Tenoplana, Taenia, Fasicola
- Tenoplana belongs to **Ctenophora** (diploblastic).
- Taenia and Fasicola belong to **Platyhelminthes** (triploblastic).
- **Conclusion**: This option is not entirely diploblastic.

5. **Option B**: Euspongia, Physalia, Meandrina
- Euspongia belongs to **Porifera** (diploblastic).
- Physalia (Portuguese man o' war) and Meandrina (a coral) belong to **Cnidaria** (diploblastic).
- **Conclusion**: This option consists entirely of diploblastic organisms.

6. **Option C**: Vacheria, Culex, Limulus
- All these organisms belong to **Arthropoda** (triploblastic).
- **Conclusion**: This option is not diploblastic.

7. **Option D**: Aedes, Ascaris, Hydra
- Aedes belongs to **Arthropoda** (triploblastic).
- Ascaris belongs to **Nematoda** (triploblastic).
- Hydra belongs to **Cnidaria** (diploblastic).
- **Conclusion**: This option is not entirely diploblastic.

8. **Final Answer**:
- The only option that consists solely of diploblastic members is **Option B: Euspongia, Physalia, Meandrina**.

### Summary:
The correct answer is **Option B**, which includes organisms from the phyla Porifera and Cnidaria, both of which are diploblastic.