The members of which phylum show radial symmetry ?

Options

A. Coelenterata
B. Ctenophora
C. Echinodermata
D. All of the above

Answer

To determine which phylum members show radial symmetry, let's analyze the options provided:

1. **Understanding Radial Symmetry**:
- Radial symmetry refers to the arrangement of body parts around a central axis, allowing the organism to be divided into two equal halves in multiple planes. This is common in many aquatic organisms.

2. **Analyzing the Options**:
- **Option 1: Coelenterata (Cnidaria)**: Members of this phylum, such as jellyfish and corals, exhibit radial symmetry.
- **Option 2: Ctenophora**: This phylum, which includes comb jellies, also displays radial symmetry.
- **Option 3: Kinodermata (Echinodermata)**: Adult echinoderms, like starfish and sea urchins, show radial symmetry, although their larvae are bilaterally symmetrical.
- **Option 4: All of the above**: Since all the phyla listed (Coelenterata, Ctenophora, and Kinodermata) exhibit radial symmetry, this option is also valid.

3. **Conclusion**:
- Since all the mentioned phyla (Coelenterata, Ctenophora, and Kinodermata) exhibit radial symmetry, the correct answer is **"All of the above."**

### Step-by-Step Solution:
1. **Define Radial Symmetry**: Understand that it allows organisms to be divided into equal halves around a central axis.
2. **Evaluate Each Option**:
- Coelenterata: Radial symmetry is present.
- Ctenophora: Radial symmetry is present.
- Kinodermata: Adult forms exhibit radial symmetry.
3. **Select the Correct Answer**: Since all options show radial symmetry, the answer is "All of the above."