Which factor in the southwestern desert ecosystem is considered abiotic?

• A. Amount of sunlight
• B. Kangaroo rat
• C. Desert tortoise
• D. Cactus population

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the difference between abiotic and biotic factors. Abiotic factors are non-living components of an ecosystem that influence living organisms, such as sunlight, temperature, water, and soil. Biotic factors are living components, such as plants, animals, and microorganisms.
2. Step 2: Analyze the options provided in the problem. Identify which options represent living organisms (biotic factors) and which represent non-living components (abiotic factors).
3. Step 3: Recognize that 'Amount of sunlight' is a non-living factor that affects the ecosystem, making it abiotic. Sunlight influences photosynthesis in plants and regulates the behavior and survival of animals.
4. Step 4: Confirm that the other options—'Kangaroo rat,' 'Desert tortoise,' and 'Cactus population'—are living organisms, and therefore biotic factors.
5. Step 5: Conclude that the correct answer is 'Amount of sunlight,' as it is the only abiotic factor listed in the southwestern desert ecosystem.