Why Do the Sand Dunes in the West Vary from Those

question 6

Multiple Choice

Why do the sand dunes in the west vary from those in the east in the figure below?

• A) The average size of the sand clasts differs in the two areas.
• B) There is slightly more rain to the east.
• C) The material to the east is closer to an igneous-rock source area, from which the dune sediment is significantly derived.
• D) The winds are predominantly in one direction in the west but blow more complexly in the east.

---

Definitions:

ENSO Event

A periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting climate globally (El Niño-Southern Oscillation).

Global Environment

Refers to the international context of environmental conditions, including climate change, biodiversity, and human impacts on Earth's ecosystems.

Soil Microorganism Respiration

The metabolic process by which soil microorganisms convert organic matter into carbon dioxide and energy.

Human Combustion

A supposed phenomenon where a human body allegedly catches fire and burns as a result of internal chemical reactions, without an external source of ignition.