Which of the following pairs of animals comprise 'Combjellies'?

Options

A. Balanoglossus and Saccoglossus
B. Pleurobranchia and Ctenoplana
C. Sea anemone and sea pen
D. Sea lily and brittle star

Answer

To solve the question "Which of the following pairs of animals comprise 'Comb jellies'?", we will analyze each option provided.

### Step-by-Step Solution:

1. **Understand the Term 'Comb Jellies'**:
- Comb jellies are marine invertebrates belonging to the phylum Ctenophora. They are characterized by their unique method of locomotion using cilia.

2. **Evaluate Each Option**:
- **Option 1: Planoglosses and Psychoglosses**:
- These animals belong to the phylum Hemichordata, not Ctenophora. Therefore, this option is incorrect.

- **Option 2: Plurobranchia and Tenoplana**:
- Both Plurobranchia and Tenoplana are indeed part of the phylum Ctenophora, which classifies them as comb jellies. Thus, this option is correct.

- **Option 3: Sea Anemone and Sea Pen**:
- Both of these belong to the phylum Cnidaria. Since they are not part of Ctenophora, this option is incorrect.

- **Option 4: Sea Lily and Brittle Star**:
- These organisms belong to the phylum Echinodermata. Therefore, this option is also incorrect.

3. **Conclusion**:
- After evaluating all options, the correct answer is **Option 2: Plurobranchia and Tenoplana** as they comprise the group known as 'Comb jellies'.

### Final Answer:
The correct pair of animals that comprise 'Comb jellies' is **Plurobranchia and Tenoplana**.