A clear confluent "lawn" of bacteria is called a
A)cell lysis
B)phage
C)Pock
D)Plaque

Which of the following contributes to the difficulty in establishing the etiology of cancer?
A)viruses are difficult to bserve
B)Most viral particles can infect cells without inducing cancer
C)cancer may not develope until long after infection
D)cancers do not seem to be contagious.
E)All of the above

Nontoxic strains of vibrio cholerae can become toxic when they are in the human intestine with toxic strains of bacteria. this suggests that the toxin genes are aquired by
A)Transduction
B)Prions
C)Host enzymes
D)None of the above

the most common route of accidental AIDS transmission to health-care workers is
A)Needlestick
B)Enviromental surface contact
C)fecal-Oral
D)Mouth to mouth
E)Aerosol

An infectious protein is a
A)Prion
B)Viroid
C)Bacteriophage
D)Retrovirus
E)None of the above

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United States