Humans acquire typhoid fever by
A. ingesting water or food contaminated with feces.
B. mosquito bites.
C. inhalation of contaminated dust particles.
D. sexual activity.
Answer: A
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Earthworms use ________ as their respiratory surface
A) lungs B) gills C) their skin D) tracheae
The evolutionary history of an organism is its
1.taxonomy 2.species 3.systematics 4.phylogeny 5.anatomy
All EXCEPT which of the following is a possible
bottleneck for a population? a. contagious disease b. widespread pesticide application c. habitat loss d. protective endangered species legislation e. persistent drought
Heinz Fraenkel-Conrat induced point mutations in the genes encoding coat proteins of TMV and looked for changes in the resulting proteins
By examining the effect of single-base changes in the mRNA on the amino acid sequence, Conrat proved that __________. A) the genetic code is overlapping B) the genetic code is nonoverlapping C) the genetic code is redundant D) there are 20 amino acids E) the genetic code is triplet