Which of the following is not a character of the enhinderm life cycle ?

Options

A. Radial symmetry
B. Bilateral symmetry
C. Asymmetrical
D. Both (A) and (C)

Answer

To solve the question "Which of the following is not a character of the echinoderm life cycle?" we will analyze the options provided:

1. **Radial Symmetry (A)**: Echinoderms, such as starfish and sea urchins, exhibit radial symmetry as adults. This means that if you were to draw lines through the center of the organism, the resulting halves would be symmetrical.

2. **Bilateral Symmetry (B)**: Echinoderm larvae are bilaterally symmetrical. This means that they have a distinct left and right side, and if you were to draw a line down the center, both sides would mirror each other.

3. **Asymmetrical (C)**: Asymmetry means that there is no symmetry; if you draw a line through the center, the two halves would not be equal. Echinoderms do not exhibit asymmetry in their life cycle.

4. **Both A and C (D)**: This option suggests that both radial symmetry and asymmetry are not characters of the echinoderm life cycle, which is incorrect since radial symmetry is indeed a character of adult echinoderms.

Now, based on the analysis:

- **Radial symmetry** is a character of adult echinoderms.
- **Bilateral symmetry** is a character of echinoderm larvae.
- **Asymmetry** is not a character of echinoderms.

Thus, the correct answer is **C, asymmetrical**.

### Step-by-Step Solution:
1. Identify the characteristics of echinoderms.
2. Analyze the symmetry types: radial symmetry for adults and bilateral symmetry for larvae.
3. Determine which option does not apply to echinoderms.
4. Conclude that asymmetry is not a character of echinoderms.