Tentacles are absent in
(a) Beroe
(b) Ctenoplane
(c) Hormiphora
(d) Obelia

Options

A. Beroe
B. Ctenoplane
C. Hormiphora
D. Obelia.

Answer

To solve the question regarding which organism lacks tentacles, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks which of the listed organisms does not have tentacles.

2. **Identify the Organisms**: The options provided are:
- (a) Beroe
- (b) Ctenoplane
- (c) Hormiphora
- (d) Obelia

3. **Define Tentacles**: Tentacles are appendages that are often found in various organisms, serving functions such as sensory perception, offense, and defense.

4. **Analyze Each Option**:
- **Beroe**: This is a type of comb jelly (Ctenophora) known for its transparent, sac-like body structure. Importantly, Beroe does not have tentacles.
- **Ctenoplane**: This organism is also a type of comb jelly and possesses tentacles.
- **Hormiphora**: This organism is known to have tentacles as well.
- **Obelia**: This organism, which belongs to the class Hydrozoa, also has tentacles.

5. **Conclusion**: Based on the analysis, Beroe is the only organism listed that lacks tentacles.

6. **Final Answer**: Therefore, the correct answer is (a) Beroe.