previous studies indicate about half of global warming is caused by carbon
dioxide gas from fossil fuel burning, about 20 percent is due to chemicals called
chlorofluorocarbons, of CFCs, and an additional 20 percent is caused by methane,
which is natural gas. Other trace gases cause the remaining warning
a. Methane,natural gas increase future temperature.
b. Fossil fuel burning heats earth's atmosph.
c. Chlorofluorocarbons CFCs are dangerous chemicals.
d. Carbon dioxide, CFCs,and methane cause global warming.