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♻️ap environmental science review

R horizon in AP Environmental Science

Written by the Fiveable Content Team
Verified for the 2027 exam
Verified for the 2027 exam•Written by the Fiveable Content Team

Definition

The R horizon refers to unweathered bedrock that lies beneath all other layers of soil. It consists of solid rock that has not undergone any significant weathering or decomposition.

AP course connection

Topic 4: Unit 4 Overview: Earth Systems and Resources

Unit 4

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