Natural gas can be burned directly or separated into methane and other gases, including propane, butane, and ethane. Which of the following is true of these component gases when compared to unrefined natural gas?
s
1. They have a lower heat value when burned.
II. Their purification results in less net air pollution.
III. They are more efficient for certain specific purposes.
Your
O l only
O III only
I and II only
O I and III only
on
I, II, and III