Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition Lac– strain, called lac3–, is linked to the Tn5 insertion. From a strain carrying the Tn5 insertion and lac3– mutation you isolate an F’ that caries a region of the chromosome that includes both Tn5 and the linked Lac region. Introduce this F’ into an F– strain carrying lac1– by selecting for Kanr. These merodiploids express ß-galactosidase normally. If the merodiploid were Lac–, 

a) the two mutations lie in the different gene.

b) Both mutation are complement each other

c) the two mutations lie in the same gene.

d) Both of the mutations is dominant to wild type.

what could you conclude about the relationship between the lac3– and lac1– mutations from  these statements?

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#Question id: 12362

#Unit 10. Ecological Principles

Using the Lincoln index to estimate the population size of wolves, you capture, mark, and release 20 wolves during the precensus period. In the census period 13 marked and 5 unmarked wolves are captured. What is the estimate of the size of the population of wolves that occupy your backyard?

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#Question id: 12363

#Unit 10. Ecological Principles

Relative to populations with long prereproductive periods, populations with short prereproductive periods tend to

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#Question id: 12364

#Unit 10. Ecological Principles

Which of the following populations is capable of increasing more rapidly than the others?

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#Question id: 12365

#Unit 10. Ecological Principles

The age pyramid of a human population that is rapidly growing due to a high reproductive rate

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#Question id: 12371

#Unit 10. Ecological Principles

Succession results from disturbance by fire.

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#Question id: 12372

#Unit 10. Ecological Principles

In a particular case of secondary succession, three species of wild grass all invaded a field. By the second season, a  single species dominated the field. A possible factor in this secondary succession was