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Part 1 of 2 - 100.0/ 100.0 PointsQuestion 1 of 405.0/ 5.0 Points__________ experts maintain that there is still time to address environmental problems and change our course toward a sustainable future.A. All B. Some C. Most D. Very few Question 2 of 405.0/ 5.0 PointsExtinctions are not rare. Over an extended period of time, based for example on fossil evidence, a certain number of species will become extinct each year. Thus, experts can estimate a background rate of species extinction. Using that estimate, researchers can compare it to the current extinction rate over, for example, the last two decades. What they have found is startling.According to cautious estimates, the current extinction rate is __________ times greater than thebackground rate.
Question 3 of 405.0/ 5.0 PointsPhytoplankton, aside from being the base of the oceanic food chain, produce __________ percent of our planet’s atmospheric oxygen.
Question 4 of 405.0/ 5.0 PointsAccording to the EPA, the second most significant factor in human-caused global warming and climate change is:
Question 5 of 405.0/ 5.0 PointsWhich of these atmospheric layers enables radio transmissions?A. Troposphere B. Stratosphere C. Ionosphere D. Thermosphere Question 6 of 405.0/ 5.0 PointsWhich of these planets is in the so-called “Goldilocks Zone”?
Question 7 of 405.0/ 5.0 PointsThe __________ harbors the largest tropical forest on the planet.
Question 8 of 405.0/ 5.0 PointsWhich of these side effects of urban sprawl is mainly related to driving time spent commuting from the “burbs” to urban workplaces?Question 9 of 405.0/ 5.0 PointsChlorofluorocarbons (CFCs), the main culprit in the depletion of atmospheric ozone, are being replaced with hydrofluorocarbons (HFCs), thus greatly reducing ozone layer depletion. What is the only drawback to this strategy?
A. HFCs give off an unpleasant odor. B. HFCs are potent greenhouse gases. C. HFCs are more expensive to produce than CFCs. D. HFCs are toxic to wildlife.