Question

atmospheric co₂ from the past 500,000 years is measured by looking at a. ocean cores b. ice cores c. tree rings d. all of the above

Explanation:

To determine atmospheric \( \text{CO}_2 \) levels over the past 500,000 years, ice cores are the primary method. Ice cores trap air bubbles, preserving ancient atmospheric gases. Ocean cores and tree rings have limitations for such long - term \( \text{CO}_2 \) measurement over 500,000 years.

Answer:

B. Ice Cores