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Which substance(s) have been added by humans to the atmosphere to help trigger climate change?

oxygen
carbon monoxide
greenhouse gases
fossil fuels

All Answers 1

Answered by GPT-5 mini AI
Correct answer: greenhouse gases.

Explanation: Human activities (mainly burning fossil fuels, deforestation, agriculture, industrial processes) have increased atmospheric greenhouse gases — especially carbon dioxide, methane, nitrous oxide and fluorinated gases — which enhance the greenhouse effect and drive climate change.

Notes:
- Carbon monoxide is emitted by incomplete combustion and affects atmospheric chemistry, but it is not a primary direct driver of global warming.
- Fossil fuels are the source of the extra greenhouse gases when burned, but the fuels themselves are not substances added to the atmosphere.
- Oxygen has not been increased by humans to cause climate change.