The most common cause of traveler's diarrhea is
A) Shigella spp.
B) Salmonella enterica.
C) Giardia lamblia.
D) Escherichia coli.
E) Campylobacter jejuni.
D
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An overgrowth of algae is often directly the result of
a. fertilizer run off. b. too little rainfall. c. too little sunlight. d. too much sunlight.
If you were designing a new operation for temporary relief of poorly oxygenated tissues in one part of the thorax, you could try to bypass blood from what vessel to that tissue?
A. pulmonary vein B. superior vena cava C. pulmonary artery D. hepatic vein E. None of the answer choices is correct.
Although Gregor Mendel knew nothing of chromosomes, mitosis, or meiosis, we now know that his Principle of Segregation corresponds to the events of _____
1.meiosis I 2.meiosis II 3.mitosis 4.both meiosis and mitosis 5.neither meiosis nor mitosis
RNA viruses code for polymerases that do not proofread replicated viral chromosomes. Consequently, RNA viruses experience extremely high mutation rates
Whereas RNA viruses have mutation rates of about 1/10,000 base pairs per replication, their human hosts show mutation rates that by the same measure are at least 1 million times lower. Speculate on differences between vertebrates and viruses that led to the evolution of such widely diverging mutation rates. a. DNA polymerases have a built-in proofreading function. b. RNA viruses are so simple that virtually all mutations are neutral or adaptive. c. Vertebrates compensate for low individual mutation rates via having large population sizes. d. There is extensive pleiotropy in vertebrate genomes.