According to a group of researchers,(A)biack carbon,emitting from biomass burning,(B)diesel engine exhaust and cooking fires,has a warming effect on theatmosphere.(C)three to four times greater than prevailing estimates.(D)

According to a group of researchers,(A)biack carbon,emitting from biomass burning,(B)diesel engine exhaust and cooking fires,has a warming effect on the

atmosphere.(C)three to four times greater than prevailing estimates.(D)