Source: Kaplan GED Test Prep 2022–2023 by Caren Van Slyke Authority Tier: Commercial Preparation (
TIER_3_COMMERCIAL) | License: Restricted Reference (RESTRICTED) Coverage: Chapter 3: Earth and Space Science (Pages 1170–1190) Curriculum Standard: High School Equivalency Preparation
Kaplan Reference: Chapter 3: Earth and Space Science
Lesson 1: Structure of Earth
(Page 1170)
CHAPTER 3 Earth and Space Science Lesson 1: Structure of Earth Earth is almost spherical, flattened at the poles, and bulging at the equator. It is composed of three main layers: the crust, the mantle, and the core. Earth’s outer layer, its solid crust , is made of granite, basalt, gabbro, and other types of rock. Under the oceans, the crust is 3 to 6.8 miles thick; under the continents, the crust is from 12 to 40 miles thick. Below the crust is the molten mantle ; it consists of silica and metal-rich minerals. The core has two