Minimum strength of stimulus required to initiate muscle contraction is .......... .

Explanation

To answer the question regarding the minimum strength of stimulus required to initiate muscle contraction, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Muscle Contraction**:
- Muscle contraction refers to the process where muscles tighten and shorten. This is essential for movement and various bodily functions.

2. **Identifying the Stimulus**:
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