The process by which microorganisms attach themselves to hostcells is _____________.
A. Infection
B. contamination
C. disease
D. adhesion
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In which type of symbiosis do both members benefit from theirinteraction?
A. Mutualism
B. parasitism
C. commensalism
D. all above.
When pathogenic bacteria lose the ability to make adhesins owing to insertion of Tn5 into the gene of pili, they typically ________________.
A. become avirulent
B. produce modified enzyme to break kanamycine
C. Produce endotoxin
D. decrease in virulence
Which statement about normal flora are right __________.
A. Inhibit R plasmid spread among different bacteria species.
B. Activate immune cells;
C. Antagonism against foreign bacteria;
D. Provide Vit.K to the host;
Directions: There are 10 incomplete sentences in this part. For each sentence there are 4 choices marked A, B, C and D. Choose the answer that best completes the sentence.1. She held her hands above her eyes to ______them ______ the sun so that she could see more clearly the man in front of her.
A. count … on
B. make sense … of
C. reserve … for
D. shield … from