Question

how soil forms
if the statement is true, write true. if the statement is false, change the underlined word or words to make the statement true.

1. ______ another name for the () horizon is
2. ______ soil that is rich in humus generally has low fertility
3. ______ outcrop is the solid layer of rock beneath soil
4. ______ soil loam depends on the size of rock particles in soil
5. ______ the o horizon consists of weathered bedrock
6. ______ you can use the ph scale to measure how acidic a soil is

write the letter of the correct answer on the line at the left.

1. __ which soil layer contains little humus but much clay and other rock particles?

a a horizon
b b horizon
c c horizon
d bedrock

1. __ what moves to soil to weather rock particles, dissolve, or, and water?

a carbonic acid
b acid rain
c oil
d

Explanation:

To solve question 7 (Which soil layer contains little humus but much clay and other rock particles?):

Step 1: Recall Soil Horizons

• A horizon (topsoil): Rich in humus, organic matter, and minerals, with moderate clay.
• O horizon: Organic layer (decomposing leaves, etc.), high humus.
• C horizon: Consists of partially weathered parent material (rock fragments, clay), little humus.
• Bedrock: Solid rock, no clay/rock particles in “soil” form.

Step 2: Match the Description

The question asks for a layer with little humus but much clay and rock particles. The C horizon fits this (partially weathered parent material, low humus, high clay/rock fragments). The options:

• A: A horizon (high humus) → Eliminate.
• B: O horizon (high humus) → Eliminate.
• C: C horizon → Matches.
• D: Bedrock (solid rock, no “clay/rock particles” in soil form) → Eliminate.

Answer:

C. C horizon