Emissions of all the following have declined since 1970 EXCEPT A
Small Particulate Matter (PM10)
B. sulfur dioxide
C. ground level ozone
D. nitrogen dioxide
E. carbon dioxide

Food can come from sustainable or unsustainable resources. why has the united nations suggested that bugs could be a better source of food than animals like pigs or cattle?

Which revelation resulted from the observation of the spectrum of different galaxies? a. there were more galaxies whose spectrum was blueshifted b. there were no galaxies whose spectrum was redshifted c. there were more galaxies whose spectrum was redshifted d. there were no galaxies whose spectrum was blueshifted

What id the primary human cause of the global warming a. storage of nuclear fuel rods b. burning of fossil fuels c. building of high-density housing d. violent conflicts over natural resources