In breathing movements, air volume can be estimated by

Options

A. stethoscope
B. hygrometer
C. Sphygmomanometer
D. Spirometer

Explanation

To solve the question "In breathing movements, air volume can be estimated by," we can follow these steps:

### Step 1: Understand the Question
The question is asking which device is used to estimate the volume of air involved in breathing movements.

### Step 2: Analyze the Options
We have four options to consider:
1. Stethoscope
2. Hygrometer
3. Sphygmomanometer
4. Spirometer

### Step 3: Evaluate Each Option
- **Stethoscope**: This device is used to listen to internal sounds of the body, such as heartbeats and lung sounds, but it does not measure air volume.

- **Hygrometer**: This device measures the moisture content in the atmosphere (humidity) and is not related to breathing or air volume.

- **Sphygmomanometer**: This device is used to measure blood pressure and does not relate to the measurement of air volume in breathing.

- **Spirometer**: This is a device specifically designed to measure the volume of air inhaled and exhaled during breathing movements. It is commonly used in clinical settings to assess pulmonary function.

### Step 4: Identify the Correct Answer
Based on the evaluations, the correct answer is **Spirometer**, as it is the only device that measures the volume of air involved in breathing.

### Final Answer
In breathing movements, air volume can be estimated by the **Spirometer**.

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