What are parallels?

Parallels refer to lines of latitude that run horizontally around the Earth. They are used to indicate the position of locations north or south of the Equator, which is defined as 0 degrees latitude. Each parallel is measured in degrees, with the North Pole at 90 degrees north and the South Pole at 90 degrees south.

Lines of latitude help in navigation, cartography, and understanding climate zones. For instance, the Tropic of Cancer lies at approximately 23.5 degrees north latitude, while the Tropic of Capricorn is at about 23.5 degrees south latitude. This designation allows for a systematic way to locate points on the Earth's surface.

The other choices refer to different concepts altogether. Lines of longitude, for example, are vertical lines that run from pole to pole, measuring the distance east or west of the Prime Meridian. Lines of elevation pertain to altitude, and lines of demarcation are used to mark boundaries, which do not relate to the measurement of geographical coordinates like parallels do. Thus, the definition and application of parallels are clearly linked to latitude.