What do contour lines represent on maps?

Contour lines on maps are utilized to illustrate the relationship between altitude and atmospheric pressure. Specifically, they connect points on a map where the altitude at which a specific pressure level occurs remains constant. This is essential in meteorology as it allows for the visualization of how pressure changes with altitude, which can be crucial for understanding weather patterns and phenomena.

When these lines are closely spaced, they indicate a rapid change in altitude, which may correlate with strong vertical motions in the atmosphere or areas of significant weather activity. Conversely, widely spaced contour lines suggest a gentle slope and more stable atmospheric conditions. This understanding helps pilots and meteorologists interpret weather situations effectively.

The other options, while relevant to meteorology, do not accurately describe the function of contour lines on maps. They relate to different aspects of weather but do not specifically convey the relationship between altitude and atmospheric pressure, which is the primary purpose of contour lines.