Type of symmetry in hemichordates is

Options

A. Radial
B. Biradial
C. Bilateral
D. 1 and 2

Answer

To determine the type of symmetry in hemichordates, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Hemichordates**: Hemichordates are marine invertebrates that possess a true body cavity, known as a coelom. They are classified as coelomates and are triploblastic, meaning their embryos develop into three distinct germ layers: ectoderm, mesoderm, and endoderm.

2. **Identify Body Structure**: The body of hemichordates is divided into three main parts: the proboscis, collar, and trunk. This structural organization is important for understanding their symmetry.

3. **Define Symmetry Types**:
- **Radial Symmetry**: An organism exhibits radial symmetry when it can be divided into multiple identical parts around a central axis. This type of symmetry is common in organisms like cnidarians (e.g., jellyfish) and echinoderms (e.g., starfish).
- **Bi-radial Symmetry**: This is a subtype of radial symmetry where the organism can be divided into two identical halves along two planes. This type is seen in organisms like ctenophores (comb jellies).
- **Bilateral Symmetry**: An organism shows bilateral symmetry if it can be divided into two identical halves along a single plane (the midline). This is typical of many animals, including humans and many invertebrates.

4. **Analyze Hemichordate Symmetry**: Hemichordates, such as the acorn worm (e.g., Balanoglossus), can be divided into two identical halves along a single midline. This indicates that hemichordates exhibit bilateral symmetry.

5. **Conclusion**: Based on the analysis, the type of symmetry in hemichordates is **bilateral symmetry**.

### Final Answer:
The type of symmetry in hemichordates is **bilateral symmetry** (Option 3).

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