Question

soil classification is partially determined by the presence of organic material, such as humus. which would have more humus - a desert or a forest - and why? check all that apply.

☐ a forest because it has more trees to provide plant litter
☐ a desert because it has soil with a larger particle size
☐ a forest because it has more animals to mix the soil
☐ a forest because the trees prevent rain from reaching the soil
☐ a desert because the dry air decomposes plant litter

Explanation:

• Option a: Forests have more trees, so more plant litter (source of organic material like humus) is produced, so this applies.
• Option b: Humus is related to organic material, not soil particle size. Desert and forest soil particle size isn't the main factor for humus here, so this does not apply.
• Option c: More animals in forests can help mix organic material into soil, increasing humus, so this applies.
• Option d: Trees in forests actually help capture and direct rain to soil (e.g., through canopy drip), they don't prevent rain from reaching soil. So this does not apply.
• Option e: In deserts, dry air slows decomposition (not decomposes faster), so plant litter decomposes slowly, leading to less humus. So this statement is incorrect (it says dry air decomposes plant litter, but in reality, dry air slows decomposition), so this does not apply. Wait, re - evaluating: The question is which has more humus. Forests have more humus. The reasoning for option e: If it said desert has less humus because dry air slows decomposition (so plant litter doesn't decompose to form humus), but the option says "a desert because the dry air decomposes plant litter"—which is wrong because dry air doesn't decompose plant litter quickly (decomposition needs moisture and microbes). So option e's reasoning is incorrect. So the correct options are a and c.

Answer:

a. a forest because it has more trees to provide plant litter
c. a forest because it has more animals to mix the soil