A compass works ____.

Options

A. Only on high mountains
B. Only on oceans or seas
C. Only in forests
D. At all places within the earth's magnetic field.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Compass**: A compass is an instrument that helps in navigation by indicating direction. It contains a magnetic needle that aligns itself with the Earth's magnetic field.

2. **Function of the Compass Needle**: The compass needle is a small magnet that is free to rotate. When the compass is held level, the needle will point towards the magnetic north and south poles of the Earth.

3. **Earth's Magnetic Field**: The Earth generates a magnetic field that extends around the planet. This magnetic field is what the compass needle reacts to, allowing it to indicate direction.

4. **Where Does a Compass Work?**: A compass works effectively in any location where the Earth's magnetic field is present. This includes all environments such as mountains, oceans, forests, and urban areas.

5. **Conclusion**: Therefore, a compass works at all places within the Earth's magnetic field. This means it can be used universally for navigation.

**Final Answer**: A compass works at all places within the Earth's magnetic field.

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