What is a key characteristic of grid lines on a map?

The correct answer identifies that grid lines on a map, particularly those representing lines of latitude and longitude, become closer together as they approach the poles. This phenomenon occurs because the Earth is a sphere. Lines of latitude, which run parallel to the equator, are spaced evenly apart only along the equator. However, as you move towards the poles, these lines of latitude converge, which results in them being more closely spaced.

Longitude lines, on the other hand, also converge at the poles, indicating that they are farthest apart at the equator and come together as one approaches either the North or South Pole. This characteristic is crucial for understanding how maps represent the spherical nature of the Earth, allowing for accurate navigation and geographical representation.

The alternative options do not accurately capture this important aspect of map grid lines. For instance, the idea that grid lines are evenly spaced everywhere on Earth overlooks the convergence effect due to the planet's curvature. Similarly, suggesting that grid lines are more distant in mountainous regions does not apply because the distance of these lines is primarily a function of latitude rather than changes in elevation.