1 Which human activity most directly causes a
significant increase in the amount of carbon
dioxide in the atmosphere?
(1) growing corn for food
(2) not using products containing plastics
(3) driving cars long distances
(4) planting large numbers of trees
2 In an effort to reduce the number of deaths due
to malaria, scientists have successfully introduced
a gene into mosquitoes. The gene makes the
mosquitoes unable to support the development
of the parasite that causes malaria. The technique
used to produce this new variety of mosquito is
most likely
(1) chromatography
(2) genetic engineering
(3) electrophoresis of genes
(4) selective breeding