What does Arc C D E describe?

Answer the above statement is correct (true);

Answer light in color; silica-rich;

The bottom part thats where most farming goes on

Each meridian forms half of a great circle, assuming a spherical earth. meridians intersect lines of latitude (parallels) at right angles. the spherical earth is divided into  360 degrees   east-west. lines of longitude range from 0° to  180° to the east and from 0° to -180 ° to the west of the prime meridian.