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Question
The rRNA gene sequences of hyperthermophilic Archaea and Bacteria have diverged ________ over time, likely due to ________.A) relatively little / strong constraints on sequence changes at higher temperatures
B) substantially / higher mutation rates at higher temperatures
C) relatively little / low mutation rates in these ancient organisms
D) substantially / DNA damage at higher temperatures
Answer
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Which of the following statements about chlamydial infections is TRUE?
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The Spanish flu of 1918 was caused by an ________ influenza virus.
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In just over a decade of efforts, the World Health Organization (WHO) eradicated smallpox by using worldwide
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In 2003, the majority of AIDS deaths occurred in
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B) prevalence / mortality
C) mortality / morbidity
D) morbidity / mortality
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Cholera is an example of a pandemic disease that
A) has multiple wild animal reservoirs and is thus difficult to eradicate.
B) spreads from a common source and could be controlled with adequate clean water and waste sanitation measures.
C) is spread through direct contact and has only a human reservoir.
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Q:
Influenza pandemics occur cyclically because
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A) clonal anergy
B) clonal deletion
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Q:
An individual usually expresses ________ structurally distinct allele(s) that encode class I MHC proteins.
A) one
B) two
C) four
D) six