What defines the equator in terms of latitude?

The equator is defined as 0 degrees latitude because it is the baseline for measuring latitude across the globe. Latitude is the geographic coordinate that specifies the north-south position of a point on the Earth's surface, and it is measured in degrees. The equator divides the Earth into the Northern and Southern Hemispheres and is equidistant from the North and South Poles, which are located at 90 degrees latitude (north and south, respectively).

By defining the equator at 0 degrees, it allows for a systematic way of understanding and mapping locations on Earth, with positive values indicating locations north of the equator and negative values indicating those to the south. This system is essential for navigation, geography, and understanding climate zones.

Since other options refer to latitude measurements that define the poles or are intermediate positions, they do not accurately describe the equator, which stands uniquely at the starting point of the latitude scale.