Which of the following best explains why deserts are considered a crucial biome on Earth, despite their small supplies of water?

• A. Deserts are the primary source of freshwater for most terrestrial organisms.
• B. Deserts have the highest rates of photosynthesis among all biomes.
• C. Deserts support unique biodiversity and play important roles in global nutrient cycles.
• D. Deserts cover only a negligible portion of Earth's land surface and have little ecological impact.

Answer: (C)

Verified step by step guidance

1. Step 1: Begin by understanding the characteristics of deserts as a biome. Deserts are defined by their arid conditions, receiving less than 25 cm of rainfall annually, and are known for extreme temperature variations.
2. Step 2: Consider the ecological importance of deserts. Despite their limited water supply, deserts support unique biodiversity, including specialized plants, animals, and microorganisms adapted to survive in harsh conditions.
3. Step 3: Examine the role of deserts in global nutrient cycles. Deserts contribute to processes such as the movement of dust and minerals, which can fertilize other ecosystems like rainforests and oceans, influencing global ecological balance.
4. Step 4: Evaluate the incorrect options. Deserts are not the primary source of freshwater, nor do they have the highest rates of photosynthesis due to limited water and vegetation. Additionally, deserts cover a significant portion of Earth's land surface, making their ecological impact substantial.
5. Step 5: Conclude that the correct explanation is: 'Deserts support unique biodiversity and play important roles in global nutrient cycles,' highlighting their ecological significance despite their arid nature.