Of all of the chordate groups, why are there only two amniote groups (reptilia and mammalia)?
A) Amniotes are the only chordate group that has successfully survived the transition to land.
B) The other craniate groups had brains that were not developed enough to allow the organisms to develop tool-building survival skills.
C) The vertebral columns of the other vertebrates were not strong enough to survive the transition to land.
D) The other jawed vertebrates were not able to obtain enough food to survive the transition to land.
Answer: A
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Recommended guidelines for laboratory microbiological precautions should reflect the laboratory's ________.
Fill in the blank(s) with the appropriate word(s).
In a pedigree chart, a male who demonstrates the trait being studied is represented by a ____
a. darkened square b. darkened diamond c. clear circle d. clear square e. darkened circle
Your research project involves the characterization of a recently identified transcription factor. As part of your project, you want to determine if this transcription factor binds directly to any of the general transcription factors. Unfortunately, you are having trouble expressing the full-length protein. What approach may help achieve your research goal?
A. You must find a way to express the full-length protein, since transcription factor functions do not lie in separate domains. B. Express and purify only the DNA-binding domain, and test for binding. C. Express and purify only the activation domain, and test for binding. D. Identify the RNA that mediates the protein-protein binding.
Despite causing a life-threatening disease, the sickle-cell allele in some areas of Africa has remained in high frequency in those populations because it protects against malaria
In the United States, malaria was eradicated shortly before World War II by eliminating the mosquito that spreads the disease. What is likely to happen to the frequency of the sickle-cell allele in African Americans living in the United States? A) The frequency of the sickle-cell allele will decrease. B) The frequency of the sickle-cell allele will not change. C) The sickle-cell allele will disappear from the African American population. D) The normal allele will disappear from the African American population. E) The frequency of the sickle-cell allele will increase.