The "lub" heart sound represents

a. a heart murmur.
b. closure of the AV valves.
c. closure of the SL valves.
d. hypertension.
e. movement of actual heart muscle.


B

Biology & Microbiology

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In the preceding experiment, bacteria that form blue colonies on X-gal/IPTG LB agar containing antibiotic also contain

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The bone tissue that consists of units called osteons is called _____ bone tissue

Fill in the blank(s) with correct word

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Mechanoreceptors are not evenly spaced on your body. What is an advantage of having mechanoreceptors located closer together?

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Which way do ocean currents circulate in the Northern Hemisphere?

a. counterclockwise b. clockwise c. away from continents

d. toward the shore e. parallel to the direction of the shore

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