Why might a compass be essential for navigation?

A compass is essential for navigation primarily because it indicates the direction relative to magnetic north. The functionality of a compass is based on the Earth's magnetic field, which allows it to point towards the magnetic poles. This ability to clearly indicate direction is crucial for travelers, explorers, and anyone needing to navigate through unfamiliar territories. Knowing the cardinal directions helps in plotting a course, determining bearings, and keeping track of movement.

The other options don't align with the compass's primary role. While knowing the distance to a destination, predicting weather changes, and determining altitude are all important aspects of navigation, they require different tools and devices, such as maps, GPS, altimeters, or weather instruments. A compass solely focuses on providing directional guidance, making it an indispensable tool for navigation.