16. What human activity has not contributed to the increasing amounts of CO_(2) in the atmosphere over the last decade? a) Frequently driving automobiles b) Burning fossil fuels c) Clear cutting of rainforests d) Overfertilizing farm fields

The correct answer is d) Overfertilizing farm fields.<br /><br />Overfertilizing farm fields does not directly contribute to the increasing amounts of $CO_{2}$ in the atmosphere. The other options, such as frequently driving automobiles, burning fossil fuels, and clear cutting of rainforests, are all human activities that have significantly contributed to the increase in $CO_{2}$ emissions over the last decade.