Many maps have a grid system, scale, and a

Many maps have a "grid system, scale and a compass rose".

Explanation:

Basic components of a map consist of symbols, legend, grid system, scale and a compass rose. Symbols in a map represent the availability, presence or existence of a particular entity at that particular place. The grid system is a system of lines intersecting each other, plotted on the map for the purpose of drawing references. The scale represents the extent to which the map has been shrunk to fit on the paper than the actual measurements of the area on the ground. And the rose compass is to show the directional orientation of the area on the map.

C.about 10% i think

Answerwill have thinner; have thicker oceanic sediments;