O157:H7, a pathogenic strain of E. coli, has more than 1,000 genes that are not present in the harmless strain K-12. Many of these genes are associated with phage DNA in the bacterial chromosome. These observations suggest that __________.
a. this virulent strain has many more R plasmids than does the harmless strain and is resistant to almost all antibiotics
b. at least some of these genes were acquired through phage-mediated horizontal gene transfer
c. at least some of these genes were acquired through phage-mediated horizontal gene transfer, and these genes were not acquired through conjugation with K-12
d. these genes were not acquired through conjugation with K-12
e. most of these novel genes must be a result of mutations and short generation times
Answer: c. at least some of these genes were acquired through phage-mediated horizontal gene transfer, and these genes were not acquired through conjugation with K-12
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Bees are currently suffering from disease, and population numbers are decreasing. What is a likely consequence for flowers if this continues?
1.There would be no need for stamens for pollination, so flowers would evolve with just carpels.
2.Other insects would take over the role of pollination for the plant.
3.Plants could go extinct if there isn’t any pollination by other organisms.
4.The plant would be forced to rely on wind for pollination.
Most nutrient absorption occurs in the ________, a major organ of the digestive system
Fill in the blank(s) with correct word
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Answer the following statement true (T) or false (F)