In humans, typically only infants produce the enzyme lactase to break down lactose. Some adults have changes in that allow transcription factors to bind and turn on expression of the lactase gene into adulthood.
A. codons
B. mRNA
C. exons
D. RNA polymerase
E. enhancers
E. enhancers
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Neurons that carry messages from the CNS to effectors are
(a) sensory. (b) motor. (c) interneurons. (d) both a and b.
A medical laboratory scientist (MLS) is examining a thin blood film from a patient suspected of having a Plasmodium infection. After examining the slide for 5 minutes and viewing approx-imately 100 oil immersion fields, the MLS does not observe any structures associated with Plasmodium. Which one of the following statements explains this discrepancy?
a. The stain may have been contaminated. b. The MLS should have examined each field under high dry magnification; there-fore the magnification is not correct. c. The MLS may have missed the organism; more than 300 fields should be viewed. d. No discrepancy is present. Plasmodium spp. are not found in blood; therefore the results are accurate.
Tertiary bronchi lead to bronchioles
a. true b. false
In simple diffusion,
a. the rate of movement of molecules is influenced by temperature and pressure. b. the movement of individual molecules is random. c. the movement of molecules of one substance is independent of the movement of any other substance. d. the net movement is away from the region of highest concentration. e. all of these happen.