Attenuation occurs in a laboratory, because
A) nonvirulent or weakly virulent mutants grow faster in vitro in laboratory media.
B) pathogens lose virulence with age.
C) patients are generally treated with drugs that induce attenuation.
D) None of the answers are correct.
Answer: A
You might also like to view...
According to the biological species concept, two groups of organisms that are unable to form fertile, viable hybrids are considered to be different
A. races. B. species. C. kingdoms. D. hybrids. E. cohabitants.
Evidence suggests that the intention to start eating triggers a decline in blood glucose. Which of the following observations supports this view?
(a) the glucose levels in the extracellular fluids that surround CNS neurons greatly decline just after eating commences (b) a rapid decline in blood glucose occurs just before eating commences (c) if an expected meal is not served, blood glucose rarely returns to its previous level (d) eliminating the premeal drop in blood glucose eliminates the meal
What part of the DNA replication process would be most directly affected if a strain of bacteria lacking DNA ligase were used to make the cell extracts?
(a) initiation of DNA synthesis (b) Okazaki fragment synthesis (c) leading-strand elongation (d) lagging-strand completion
Which of the following are found within the monomer unit of DNA?
A. fatty acids, sugars B. phosphate, amino acids C. phosphate, nitrogen bases D. nitrogen bases, fatty acid E. amino acids, nitrogen bases