Each DNA double helix has a backbone that consists of alternating ____.

A. covalent and ionic bonds
B. nitrogen-containing bases
C. hydrogen bonds
D. sugar and phosphate molecules
E. covalent and hydrogen bonds


Answer: D

Biology & Microbiology

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In all plants, gametes unite at fertilization to form a ____

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The cohesiveness between water molecules is due largely to:

a. ionic bonds. b. hydrogen bonds. c. polar covalent bonds. d. nonpolar covalent bonds. e. hydrophobic interactions.

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A consequence of the way hormones, as compared to neurotransmitters, get to their target cells is that hormones:

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Biology & Microbiology