the frequency of the wave is 13mm
15mm divided by 3 = 5 x 2= 10+3= 13mm so the answer is 13
i believe the answer is a
answer and explanation;composition refers to both the types of minerals within a rock and the overall chemical makeup of the rock while texture refers to the size and arrangement of the minerals or grains that make up a rock. both composition and texture can be used to classify rocks, such as igneous rocks. texture describes how the rock became solid or crystallized from liquid, melted rock. composition of a rock describes the minerals that make up a particular rock.