E. coli has been isolated and cultured from three different individuals. Upon biochemical testing of these three cultures, you find that there are differences in some reactions. What is the best explanation of these differences?
A. These represent three different species of E. coli.
B. This is normal genetic variation seen among strains of E. coli.
C. The other two cultures are not really E. coli.
D. Mistakes have been made in the test interpretation.
E. Two of the cultures are mutants of the other.
Answer: B
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Which of the following is NOT related to genetic drift?
A. Founder effect B. Bottleneck effect C. Sexual selection D. Neutral variation E. Non-Darwinian evolution
Fossils of Cooksonia, which date to approximately ____ years ago, represent the oldest known fossils of vascular
plants.
a. 1.5 billion b. 425 million c. 250 million d. 125 million e. 17 million
If the frequency of PKU, an autosomal recessive disease, is 1% in males, what is the frequency of females with PKU? (You may assume that the population is in Hardy-Weinberg equilibrium.)
What will be an ideal response?
Which of the following monomers is not paired correctly?
A) nucleotides-nucleic acids B) amino acids-proteins C) glucose-carbohydrates D) All of these are paired properly.