The relatively high percentage of individuals in West Africa who are heterozygous for the sickle cell trait is an
example of _____.
a. natural selection
b. genetic drift
c. spontaneous mutational spread
d. heterozygote disadvantage
e. the founder effect
ANSWER: a
You might also like to view...
Organisms in the same clade are:
A. monophyletic B. convergent C. divergent D. polyphyletic E. syntopic
The vertebrate kidney helps to keep the acidity of the body fluids constant by varying the amount of hydrogen ions (H+) it secretes into the urine
You can confidently predict that this aspect of kidney function, like other mechanisms of homeostasis, will be controlled by ________. A) a negative feedback mechanism B) nerve impulses from the brain C) a hormone produced in the brain D) a hormone produced in the kidney itself
The high body temperature of birds and mammals is due to
A) the fur that insulates them. B) their high metabolic rates. C) the presence of sweat, scent, and sebaceous glands. D) behaviors such as basking in the sun and seeking shade. E) the exchange of gases and nutrients via the placenta.
Which of the following is capable of resetting the thermostat of the body to cause a fever?
A) complement B) pyrogen C) antigen D) perforin