The lagging behind of strain is called ____

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term that describes the phenomenon of "lagging behind" of strain in relation to stress in a material.

2. **Defining Key Terms**:
- **Strain**: It is the deformation per unit length caused by stress.
- **Stress**: It is the force applied per unit area within materials.

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