Biological half-life is the time required for
A. half of an ionic compound to ionize.?B. half of a radioactive material to be eliminated from the body.?C.
radioactivity levels of organic compounds to stabilize at one-half their original value.
?D. radiation exposure that is lethal for half of a biological population.
B
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Catecholamines
a. are secreted by the adrenal cortex b. reinforce the activities promoted by the parasympathetic nervous system c. are important in the maintenance of blood pressure d. promote glycogen storage e. are secreted in response to hypothalamic stimulation
Which of the following helps maintain a high solute concentration in the kidney medulla?
A. high urea concentration in medulla B. active transport of solutes from ascending limb C. the vasa recta D. functions of the loop of Henle E. All of these choices are correct
The four primary tissue types found in adult organs include all of the following except _________ tissue.
A. connective B. fibrous C. nervous D. epithelial E. muscular
The anterior view of the heart is dominated by which chambers?
A) right atrium and right ventricle B) left atrium and left ventricle C) right atrium and left atrium D) right ventricle and left ventricle E) right atrium and left ventricle