If You Were Digging Down into a Soil, Which Horizon

question 10

Multiple Choice

If you were digging down into a soil, which horizon would you hit last?

• A) C
• B) R
• C) O
• D) B
• E) E

---

Definitions:

Nonphotosynthetic Partners

Organisms that do not perform photosynthesis but are involved in symbiotic relationships with photosynthetic organisms, often exchanging nutrients.

Oxygen

A chemical element with symbol O and atomic number 8, essential for most life forms on Earth as part of the process of respiration.

Ecological Niche

Of a species, unique set of requirements and roles in an ecosystem.

Unique Requirements

Specific needs that are particular to an individual organism, system, or process, distinguishing them from others.