The natural of ………are plants and animals respiration and decomposition of organic matters.
a) CO2
b) SO2
c) NO2
d) O2
The main source of emission of nitrogen are..
a) bacteria
b) microorganisms
c) both a & b
d) none of these
The main source of SO2 is …………
a) seed germination
b) decomposition of organic matters
c) fire forest
d) volcanic eruption
………… is produced by rock weathering.
a) SO2
b) CO2
c) NO2
d) CO
VOCs such as…………produced by wetlands are the largest natural source.
a) methane
b) oxygen
c) lithium
d) helium
VOCs contribute…………of natural methane in the environment.
a) 75%
b)76%
c) 77%
d) 78%
