Radial symmetry and lack of cnidoblasts are the characteristics of

Options

A. Starfish and sea anemone
B. Ctenoplana
C. Aurelia and paramecium
D. Hydra and starfish

Explanation

To solve the question regarding which organism exhibits radial symmetry and lacks cnidoblasts, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**:
- **Radial Symmetry**: This is a form of symmetry where the body plan is arranged around a central axis. Organisms with radial symmetry can be divided into similar halves by multiple planes passing through the central axis.
- **Cnidoblasts**: These are specialized cells found in members of the phylum Cnidaria (like jellyfish, corals, and sea anemones) that contain stinging structures called nematocysts, used for defense and capturing prey.

2. **Identify the Phyla**:
- **Phylum Cnidaria**: This includes organisms like jellyfish, sea anemones, and corals, which possess cnidoblasts.
- **Phylum Ctenophora**: This includes organisms like comb jellies, which exhibit radial symmetry but do not have cnidoblasts.

3. **Analyze the Options**:
- **Option 1: Sea Anemone** - This belongs to Cnidaria and has cnidoblasts. (Incorrect)
- **Option 2: T. lena (Tinoplana)** - This belongs to Ctenophora, exhibits radial symmetry, and lacks cnidoblasts. (Correct)
- **Option 3: Aurelia** - This is a jellyfish, also part of Cnidaria, and has cnidoblasts. (Incorrect)
- **Option 4: Hydra** - This is another member of Cnidaria and has cnidoblasts. (Incorrect)

4. **Conclusion**: The organism that exhibits radial symmetry and lacks cnidoblasts is **T. lena (Tinoplana)**, which belongs to the phylum Ctenophora.

### Final Answer:
The correct answer is **T. lena (Tinoplana)**.

---