Influenza pandemics occur cyclically because
A) less than 100% of the population is immunized.
B) new strains emerge due to reassortment between bird, swine, and human variants.
C) the vector is seasonal.
D) there are environmental reservoirs that release the virus during particular seasons.
Answer: B
You might also like to view...
Which of the following apicomplexan genera cause coccidiosis in chickens?
A. Pneumocystis B. Eimeria C. Toxoplasma D. Plasmodium
Competition for one resource often influences the ability of an organism to access other resources
Indicate whether the statement is true or false
Chance changes in a gene pool are known as ____
a. artificial selection b. genetic drift c. phenotype variations d. inheritance e. acquired characteristics
You feel discomfort and possibly pain when the dentist drills a hole in your tooth because the:a
heat of the drilling process is felt by the gum tissue. b. pulp cavity contains nerves. c. tooth decay has invaded the pulp cavity.
d. dentist is applying too much pressure to the drill. e. decay has affected the dentin.