WHAT I KNOW (Pre-Test) Directions: Write the letter of the answer that BEST completes each sentence. 1. is/are one of the most valuable abiotic factors in an ecosystem. A. Plants D. soil C. community B. insects 2. Which of the following indicates to the public the health risk of the air at a location and time? A. Air Quality Index C. Air Safety Index B. Atmospheric Safety Quotient D. Clean Air Index 3. How does increasing nitrates impact stream health? A. Excessive growth of algae C. increased oxygen B. increased water clarity D. none of the choices 4. What two gases are found throughout all layers of the atmosphere? A. Nitrogen and carbon dioxide C. Nitrogen and oxygen B. Oxygen and carbon dioxide
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1. D. soil