A diagram shows a soil profile with labels I, II, III, IV representing different horizons. Answer the following questions about the diagram: (i) What does the diagram represent? (ii) Name each labelle

Here are the answers to your questions based on the provided diagram of a soil profile:

• (i) What does the diagram represent? The diagram represents a soil profile (or soil horizons).

• (ii) Name each of the parts labelled I, II, III, IV.

  • I: O horizon (Organic layer / Humus layer)
  • II: A horizon (Topsoil)
  • III: B horizon (Subsoil)
  • IV: C horizon (Parent material / Bedrock)

• (iii) Which part of the diagram:

  • (α) is the richest in humus?
    • The A horizon (II) is typically the richest in well-decomposed humus mixed with mineral soil.
    • Answer: $\boxed{\text{II}}$
  • (β) is the habitat for soil organisms?
    • The A horizon (II) provides the best conditions (organic matter, air, moisture) for most soil organisms.
    • Answer: $\boxed{\text{II}}$
  • (γ) undergoes weathering?
    • The C horizon (IV) is the parent material that undergoes initial weathering to form soil.
    • Answer: $\boxed{\text{IV}}$

• (iv) What is the effect of heavy rainfall on the part labelled I? Heavy rainfall on part I (the O horizon/organic layer) can cause soil erosion, washing away the loose organic matter and fine soil particles. It can also lead to leaching of nutrients from this layer.