Unit Test — Unit test Answers

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21
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Review the chart, which shows the population sizes of three African animals in 1990 and in 2000. Population Estimates of Animals in Africa in 1990 and in 2000 19902000Lions100,00047,000Cheetahs25,0007,500Zebras750,000450,000Which explanation is best supported by the numbers in the chart?

A
Lion and cheetah populations compete for the food source of zebras, and lions outcompete cheetahs.
B
The dwindling zebra population has led to the decline of the predator lion and cheetah populations.
C
Overhunting of lion and cheetah populations has led to a decline in the food source population.
D
Lion and cheetah populations compete for the food source of zebras, and cheetahs outcompete lions.
22
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Ground squirrels are found in many areas of the United States. They live in underground burrows and are often attacked by birds of prey, coyotes, and bobcats. Which of the following is a limiting factor for a ground squirrel population?

A
a population of tree squirrels
B
a population of hawks
C
genetic variability
D
breeding season
23

Consider the following data. Rates for Cheetah Population from 2011 to 2012Cause of change20112012Deaths21Births54Immigration 61Emigration83Which would have to happen to keep the population growth of cheetahs in 2013 the same the previous years?

A
4 deaths, 7 births, 2 immigration, 6 emigration
B
3 deaths, 6 births, 5 immigration, 7 emigration
C
5 deaths, 2 births, 8 immigration, 3 emigration
D
1 deaths, 5 births, 3 immigration, 7 emigration
24

The Serengeti plains are part of the African savanna ecosystem and are home to a variety of different species of plants and animals. The Serengeti plains experience a seven-month period of seasonal drought each year, during which the ecosystem receives only four inches of rain and the availability of some resources becomes very scarce. Which type of limiting factors does the seasonal drought in the Serengeti plains affect?

A
density-independent factors
B
density-dependent factors
C
population-dependent factors
D
population-independent factors
25

Which is biotic?

A
soil
B
leaf
C
water
D
snow

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