What is the main cause of acid rain?
A.
burning of fossil fuels
B.
corrosive, unmaintained buildings
C.
avalanches on a mountain slope
D.
decaying insects and organisms
E.
untreated wastewater
A.
burning of fossil fuels
B.
corrosive, unmaintained buildings
C.
avalanches on a mountain slope
D.
decaying insects and organisms
E.
untreated wastewater