Let's break down the problem step by step: ### Problem Restatement **Given:** - A person releases CO₂ via respiration at an average rate of **0.97 kg/day**. - How long (in years) would it take for that person to release **4.60 metric tons of CO₂** (the annual release from a typical passenger vehicle)? - **1 metric ton = 1000 kg** --- ### Step 1: Convert Metric Tons to Kilograms \[ 4.60 \text{ metric tons} \times 1000 \frac{\text{kg}}{\text{metric ton}} = 4600 \text{ kg} \] --- ### Step 2: Find the Number of Days Needed \[ \text{Number of days} = \frac{\text{Total CO}_2 \text{ (kg)}}{\text{CO}_2 \text{ released per day (kg/day)}} \] \[ \text{Number of days} = \frac{4600 \text{ kg}}{0.97 \text{ kg/day}} \] \[ \text{Number of days} \approx 4742.27 \text{ days} \] --- ### Step 3: Convert Days to Years \[ \text{Number of years} = \frac{\text{Number of days}}{365} \] \[ \text{Number of years} = \frac{4742.27}{365} \] \[ \text{Number of years} \approx 12.99 \text{ years} \] --- ### **Final Answer** \[ \boxed{13 \text{ years (rounded to two significant figures)}} \] --- ### **Summary of Steps** 1. Convert 4.60 metric tons to kg: **4600 kg** 2. Divide total kg by daily rate: **4742.27 days** 3. Convert days to years: **13 years** **So, it would take about 13 years for a person to release 4.60 metric tons of CO₂ via respiration.**

The concept used in answering this question revolves around basic unit conversions and proportional reasoning. First, it involves converting the total amount of CO₂ from metric tons to kilograms since the daily emission rate is given in kilograms. This step ensures consistent units for calculation. Next, it applies the principle of division to determine the number of days required to accumulate the total CO₂ emission by dividing the total kilograms by the daily emission rate. Finally, converting the total days into years by dividing by 365 days per year completes the calculation. This process demonstrates how to relate a rate of emission to a total amount over time using simple arithmetic and unit conversions, which are fundamental in solving problems involving rates, time, and quantities in physics and environmental science.