In which of the following do the mucous membranes serve as a portal of entry for disease?
A) A pathogen crosses from the mother to the fetus by way of the placenta.
B) A person rubs the eye with contaminated fingers and the pathogen is washed into the nasal cavity by way of tears.
C) A person is bitten by a mosquito that carries the malaria parasite.
D) Fungi digest the outer layer of the skin.
E) A person receives an injection with a contaminated needle.
B
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When a population is small relative to its carrying capacity, its growth will be:
A. geometric. B. exponential. C. logistic. D. both geometric and exponential. E. both geometric and logistic.
Which of the following statements is false regarding the nicotinic acetylcholine receptor?
A) The actions of acetylcholine can be mimicked by nicotine. B) It binds one molecule of acetylcholine for activity. C) The open channel allows an influx of sodium ions. D) Biochemical purification was aided by cobratoxin. E) It is comprised of four large subunits.
At a source the phloem typically has a water potential that is ____ that in surrounding xylem
a. lower than b. about the same as c. higher than d. exactly the same as e. less negative than
What is an advantage to an organism producing microRNA?
A) microRNA causes mutations in unused genes. B) microRNA can protect against heart disease and cancer. C) microRNA can protect against viral infections. D) microRNA allows for the inactivation of Barr bodies.