Smooth muscles are found in all the sites mentioned below except:

Options

A. alimentary tract
B. uterus
C. oviduct
D. external muscle of the eye ball

Explanation

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks where smooth muscles are found, and it provides four options: elementary tract, uterus, oviduct, and external muscle of the eyeball. We need to identify the option that does not contain smooth muscles.

2. **Define Smooth Muscles**: Smooth muscles are a type of muscle tissue that is involuntary, meaning they operate automatically without conscious control. They are made up of spindle-shaped cells with a single central nucleus.

3. **Identify Locations of Smooth Muscles**:
- **Elementary Tract**: Smooth muscles are present here as they help in the movement of food through the digestive system.
- **Uterus**: Smooth muscles are present in the uterus, facilitating contractions during childbirth.
- **Oviduct**: Smooth muscles are also found in the oviduct, aiding in the movement of eggs from the ovaries to the uterus.

4. **Analyze the External Muscle of the Eyeball**: The external muscle of the eyeball is responsible for voluntary movements, such as blinking and moving the eyes. These muscles are not smooth muscles; they are skeletal muscles, which are under conscious control.

5. **Conclusion**: Based on the analysis, smooth muscles are found in the elementary tract, uterus, and oviduct, but not in the external muscle of the eyeball.

**Final Answer**: Smooth muscles are found in all the sites mentioned below except the external muscle of the eyeball.

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