Multiple choice

Which of the following is the most fertile layer of soil?

  1. Top soil

  2. Subsoil

  3. Bedrock

  4. Parent rock

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Topsoil (A-horizon) is the most fertile layer because it contains the highest concentration of organic matter, humus, nutrients, and biological activity. Subsoil (B-horizon) has less organic material. Bedrock and parent rock are unweathered or partially weathered rock with minimal fertility.