Premature infants are at risk of infant respiratory distress syndrome because of lack of
A. respiratory muscle strength (e.g., of the diaphragm).
B. serous fluid between the pleurae.
C. functional respiratory membrane cilia.
D. surfactant, a lipoprotein secreted in alveoli.
E. fluid clearance from airways.
Answer: D
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Ridges that anchor muscles that stabilize the head are the
A) anterior and posterior nuchal lines. B) anterior and superior nuchal lines. C) inferior and superior nuchal lines. D) medial and lateral nuchal lines. E) cranial and caudal nuchal lines.
An inhibitory presynaptic neuron can affect a postsynaptic neuron by
A) producing an IPSP in the postsynaptic neuron. B) hyperpolarizing the plasma membrane of the postsynaptic neuron. C) causing K+ to diffuse out of the postsynaptic neuron. D) causing Cl- to diffuse into the postsynaptic neuron. E) all of the above.
Which of the following is NOT true of glycolysis?
A) Two molecules of ATP are spent. B) Four molecules of ATP are synthesized. C) Glucose is split into two three-carbon pyruvate molecules. D) Four molecules of NADH are spent.
The thymus contains lymphatic cells as well as secretory ________ tissue.
A. osseous B. epithelial C. muscle D. areolar E. neural