The aspect of his experimental process which is most important for obtaining reliable results is repeating his data collection many times.
Both were powerful nations and they served as trading hubs in their respective regions during that time.
The right option is A. hydrofluorocarbons
Hydrofluorocarbons are pollutants that are likely to be produced from air conditioning.
Hydrofluorocarbons (HFCs) are synthetic fluorinated strong greenhouse gases that are strongly accumulating in the atmosphere. Hydrofluorocarbons are mainly used as refrigerants. Hydrofluorocarbons are used to replace ozone depleting substances such as chlorofluorocarbons and hydrochlorofluorocarbons which are being phased out in air conditioning, refrigeration, foam blowing agents, and solvents. Hydrofluorocarbons are responsible for about 20% of climate pollution by 2050
