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Question
Explain why only anaerobic bacteria inhabited Earth for the first two billion years of its existence.Answer
This answer is hidden. It contains 69 characters.
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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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Diseases can be controlled through immunization even if the percentage of the population that is immunized is less than 100% because
A) vectors can be controlled through other means.
B) most diseases lack reservoirs.
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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.
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C) is spread through direct contact and has only a human reservoir.
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Influenza pandemics occur cyclically because
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C) the vector is seasonal.
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B) can be virtually any pathogenic bacterium or virus.
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The arrangement of Class II MHC proteins in pairs or trimers enhances their stability.
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A) clonal anergy
B) clonal deletion
C) clonal anergy and deletion
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Clonal anergy is a state of
A) antibody production.
B) high energy.
C) unresponsiveness.
D) high energy and antibody production.
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An individual usually expresses ________ structurally distinct allele(s) that encode class I MHC proteins.
A) one
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C) four
D) six