A universal characteristic of insects is

Options

A. Two pair of wings
B. Two pair of antennae
C. Two pair of antennae
D. Three pairs of thoracic legs

Answer

To determine the universal characteristic of insects, we need to analyze the given options based on their exclusivity to insects.

### Step-by-Step Solution:

1. **Understanding the Characteristics of Insects**: Insects belong to the class Insecta and have several defining features. One of the most notable characteristics is their body structure, which includes three main parts: the head, thorax, and abdomen.

2. **Evaluating the Options**:
- **Option 1: 2 pairs of Wings**: While many insects have wings, not all insects possess wings (e.g., ants, some beetles). Therefore, this characteristic is not universal to all insects.
- **Option 2: 2 pairs of Antennae**: Insects typically have one pair of antennae. Other arthropods, like crustaceans, have multiple pairs of appendages, making this characteristic not exclusive to insects.
- **Option 3: 3 pairs of Thoracic Legs**: Insects are characterized by having three pairs of legs, which are attached to the thorax. This feature is exclusive to insects and is not found in other groups of animals.

3. **Conclusion**: The universal characteristic of insects is the presence of **3 pairs of thoracic legs**. This feature is unique to insects and distinguishes them from other arthropods.

### Final Answer:
The universal characteristic of insects is **3 pairs of thoracic legs**.

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