Insect is distinguishable from crustacean by

Options

A. Number of eyes
B. Arrangement of nerve cords
C. Number of appendages
D. Presence of wings.

Answer

To determine how insects are distinguishable from crustaceans, we can analyze the provided options step by step.

### Step-by-Step Solution:

1. **Understanding the Organisms**:
- Both insects and crustaceans belong to the phylum Arthropoda. They share some common features but also have distinct characteristics.

2. **Analyzing the Options**:
- **Option 1: Number of Eyes**:
- Both insects and crustaceans typically have a pair of compound eyes. Therefore, this feature does not distinguish them.
- **Option 2: Arrangement of Nerve Cords**:
- Insects and crustaceans both have a solid, double, and mid-ventral nerve cord. This means that the arrangement of nerve cords is also not a distinguishing feature.
- **Option 3: Number of Appendages**:
- Insects have three thoracic segments, and each segment has one pair of legs, totaling six legs. In contrast, crustaceans typically have more appendages, with four pairs of legs arising from the body and two additional pairs from the head, totaling eight legs. This difference in the number of appendages is a key distinguishing feature.
- **Option 4: Presence of Wings**:
- While many insects have one or two pairs of wings, not all insects do, and crustaceans do not have wings at all. However, this feature is not consistent across all insects, making it less reliable for distinction.

3. **Conclusion**:
- The most reliable distinguishing feature between insects and crustaceans is the **number of appendages**. Insects have six legs, while crustaceans typically have eight or more.

### Final Answer:
Insects are distinguishable from crustaceans by the **number of appendages**.

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