The major source(s) of chlorofluorocarbons (CFCs) in the atmosphere was/were ________.
A) microbial fermentation of organic matter in coal mines, oil wells, and livestock
B) combustion of fossil fuels
C) refrigerants, solvents, and spray propellants
D) burning of fossil fuels and coal
E) emissions from automobile exhaust and chemical fertilizers
Question 2
Which of the following nonhuman-related causes has most likely contributed the most to the increase in malaria in Africa?
A) increased difficulty in treating malaria with antibiotics
B) growing urban populations
C) increased insecticide resistance
D) increased vulnerability of HIV-infected humans to malaria
E) less money for mosquito abatement programs