Q: What is the smallest contractile portion of a muscle? Choices: - filaments - cell - capillary - sarcomere A:
sarcomere
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Q: In how many basic was can substances cross the plasma membrane? Choices: - one - three - four - two A:
two
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Q: What can be thought of as the most biologically productive regions on earth? Choices: - swamps - forests - coasts - estuaries A:
estuaries
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Q: What can prevent the passage of molecules and ions between cells, such as in the blood-brain barrier? Choices: - fatty junctions - solid junctions - special junctions - tight junctions A:
tight junctions
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