58. The acetylcholine receptor is a ligand-gated channel that produces (A) Depolarization by allowing Na+ ions to enter the muscle fiber. (B) Hyperpolarization by allowing Na+ ions to exit the muscle fiber. (C) Depolarization by allowing Clions to enter the muscle fiber. (D) Depolarization by allowing K+ ions to leave the muscle fiber.

59. Teeth aren't exactly bones, but they're made up of similar tissues and are subject to the same problems bones may have. In what way(s) do you predict the disease rickets might affect teeth? (A) Periodontal disease: Redness and swelling elicited by bacterial infection of the gums. (B) Delayed formation: The baby teeth may not erupt until after one year. When they erupt, they may be smaller than normal. (C) Increased likelihood of cavities: Low vitamin C status prevents sufficient mineralization, allowing infection to establish on the teeth. (D) Canker sores: Painful mouth sores associated with bacteria and/or viruses.

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