Which of the following statements about positive and negative lymphocyte selection is TRUE?
A. In both instances, lymphocytes die after they do their job.
B. In both instances, antigens do not recognize pathogens in the body.
C. Only positive selection is needed for proper functioning of the immune system.
D. It is necessary to have lymphocytes that can fight invaders without harming the body's own tissues.
Answer: D
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The brain
a. consists of 90 percent interneurons and 10 percent glial cells b. can perform anaerobic metabolism when oxygen supplies are low c. normally uses only glucose as a fuel for energy production d. exhibits all of the above e. exhibits none of the above
A flat, thin structure made of dense connective tissue that serves to attach a muscle to a bone (or to another muscle) is a(n)
A. superficial fascia. B. aponeurosis. C. tendon. D. myolemma. E. perimysium.
Motor commands are carried by ________ from the brain along the spinal cord.
A. descending tracts B. both anterior and posterior roots C. spinal nerves D. cranial nerves E. ascending tracts
Which of the following surrounds a muscle fiber?
A. Endomysium B. Epimysium C. Fascia D. Perimysium