Analysis of the 1918 and 2009 flu epidemics reveals that the most likely scenario was that ________
A) the virus causing these outbreaks were derived from a single strain within which significant mutations changed the protein hemagglutinin
B) these viruses switched from using RNA to using DNA
C) the virus ultimately arose in birds, jumped to pigs, and then was able to switch to humans
D) strong selection produces particularly virulent flu strains with predictable periodicity
C
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What are the characteristics of red light, which is absorbed by chlorophylls?
A. Its photons have the shortest wavelength in the visual spectrum B. Its photons have the highest energy in the visual spectrum C. Its photons have the longest wavelength in the visual spectrum D. It is not considered a part of the visual spectrum
Which of the following is the highest (or most complex) level of structure for genetic material?
A. nucleotide. B. double helix. C. DNA. D. gene. E. chromosome.
One of the dangers of smoking is that it disrupts the defensive system that utilizes ciliary action of what type of specialized epithelium?
A. columnar epithelium B. stratified epithelium C. glandular epithelium D. cuboidal epithelium E. pseudostratified epithelium
Bacterial peptidoglycan is not a good target for antibiotics because it is present in human cells as well, leading to host damage.
Answer the following statement true (T) or false (F)