**Step-by-Step Solution:**
1. **Identify the Composition of Dry Ice**:
Dry ice is commonly known as the solid form of carbon dioxide. The chemical formula for carbon dioxide is CO₂, which consists of one carbon atom and two oxygen atoms.
2. **Understanding the Properties of Dry Ice**:
When dry ice is heated, it does not melt into a liquid form. Instead, it undergoes a process known as sublimation, where it transitions directly from a solid to a gas. This is a key characteristic of dry ice.
3. **Reason for the Name "Dry Ice"**:
The term "dry ice" is derived from the fact that when it sublimates, it does not produce any liquid water. Therefore, it does not make the surface wet, which is a common characteristic of regular ice (made of water).
4. **Conclusion**:
Based on the above points, we can conclude that dry ice is composed of solid carbon dioxide, which is represented by the chemical formula CO₂.
**Final Answer**: Dry ice is composed of solid CO₂ (solid carbon dioxide).
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