We use a ...................... for measuring the temperature of a body.

Explanation

To fill in the blank in the question "We use a ...................... for measuring the temperature of a body," we need to identify the device used for this purpose.

Step 1: Identify the device used for measuring temperature.
- The device commonly used to measure temperature is called a thermometer.

Step 2: Describe the thermometer.
- A thermometer is a device that can come in various shapes and sizes, but the most common type is a glass tube filled with mercury.

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