How do melanocytes and keratinocytes work together to protect the skin from uv damage?

The summit of chimborazo, in ecuador, which is at a distance of about 6,384 km from the earth’s center. the bottom of the mariana trench, in the western pacific ocean, which is nearly 6,370 km from the center of the earth. on the surface of earth on the equator line.

Can anybody me with this? ? (picture included.)

How do we measure or think of speed in the united states?