You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

Q: Early scientists most likely saw a discharge of electricity for the first time when observing a  
 (A) waterfall (B) rainbow (C) lightning storm (D) volcano erupting

A: C
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Q: Which explains how the epithelium offers protection to land-dwelling vertebrates?  
 (A) Epithelium provides a rigid shell to prevent punctures. (B) Epithelium has capillaries to resist iron deficiency. (C) Epithelium insulates the vertebrate from hypothermia. (D) Epithelium prevents dehydration in vertebrates.

A: D
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Q: The periodic table of the elements is systematically organized according to the  
 (A) rate at which the elements chemically react. (B) hardness of the elements. (C) structure of the atoms of the elements. (D) radioactivity of the atoms of the elements.

A:
C
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