Up until 20-30 years ago, people with cystic fibrosis (CF) wouldn't live long enough to reproduce
CF is a homozygous recessive condition, leading researchers to think that over
time the incidence of CF would decrease because the allele would be removed from the
gene pool. The results actually indicate that the rate of CF is on the rise. Which of the
following would explain those results?
A. We are being subjected to more mutations
as a population due to more pollution.
B. The population is increasing, and more
people mean more mutations.
C. The heterozygous condition is being
selected for, much like what we see with
sickle cell trait.
D. People are traveling more, so when
members from different areas reproduce,
more mutations will result.
C
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In homeostatic control, the _________ compensates for any deviation between the actual value and the set point. In body temperature regulation in mammals, this function is carried out by __________.
A. effector; skeletal muscle B. sensor; neurons C. effector; brain D. integrator; skeletal muscle E. integrator; brain
Releases hormones that control blood sugar levels by stimulating glycogen formation or breakdown
(A) testis (B) Lining of small intestine (C) Anterior pituitary (D) thyroid (E) pancreas
The MHC (major histocompatibility complex) is NOT important in
A. presenting antigenic determinants. B. recognizing infected cells. C. identifying bacterial pathogens. D. identifying abnormal cells. E. distinguishing self from non-self.
The primary reason certain plants grow well as houseplants is because they may be adapted to
A. dry growing conditions B. growing short branches C. lack of temperature changes D. areas that normally lack direct sunlight E. areas that get very little mineral content in the soils