Question

read the text. before humans developed written language, they created pictures on rocks. this
ock art\ often portrays animals or abstract designs. the pictures could have been records of events, plans, or messages. there are two basic types: pictographs and petroglyphs. pictographs were drawn or painted on the surface of rocks with pigments such as charcoal, blood, or chalk. petroglyphs, on the other hand, were scratched or carved into the rock itself. with some petroglyphs, only the surface layer of rock is removed, showing a lighter color of rock beneath the outer layer. other petroglyphs consist of carvings cut deep in the rock. most pictographs have faded, while petroglyphs have endured longer. which organizational structure does this text primarily use? problem - solution compare - contrast sequential

Explanation:

The text first introduces rock art, then presents two types (pictographs and petroglyphs). It describes how pictographs are made (drawn/painted with pigments) and how petroglyphs are made (scratched/carved into rock), and also compares their durability (pictographs faded, petroglyphs endured longer). This focuses on comparing and contrasting the two types of rock art. The problem - solution structure would involve a problem and a solution, which is not present. The sequential structure would involve a sequence of events or steps, which is also not the main focus here.

Answer:

compare - contrast