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Question 19 of 405.0/ 5.0 PointsExtinctions are not rare. Over an extended period of time, based for example on fossil evidence, a certainnumber 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 the background rate.A. 20 B. 50 C. 100 D. 300 Question 20 of 405.0/ 5.0 PointsAs the Arctic permafrost melts, the proportion of __________ to all the other greenhouse gases is rising. That’s significant since, among all greenhouse gases, that gas is eight times more potent than carbon dioxide.
Part 2 of 2 -95.0/ 100.0 PointsQuestion 21 of 405.0/ 5.0 PointsAs a demographer, you’ll know that the __________ death rate equals the total deaths per year divided by the midyear population, which is normally expressed as the number of deaths per 1,000 people per year.Question 22 of 405.0/ 5.0 PointsThe global region or country with the highest population growth rate is:Question 23 of 405.0/ 5.0 PointsIn which country have death rates declined markedly even as infant mortality rates are the highest in theworld?A. Pakistan B. India C. Afghanistan D. Nigeria
Question 24 of 405.0/ 5.0 PointsAn age pyramid provides historical information about a population. That information includes all of the following EXCEPT:Question 25 of 405.0/ 5.0 PointsInfant mortality is defined as the percentage of infants who die within __________ after birth in a given population per 1,000 live births per year.Question 26 of 405.0/ 5.0 PointsFemales tend to live longer than males. According to your reading, the discrepancy seems to be related to all of the following EXCEPT: