In lines 17-18, the author mentions the "expansion of halite crystals...by heating and of sulfates
In lines 17-18, the author mentions the "expansion of halite crystals...by heating and of sulfates and similar salts by hydration" in order to
A. present an alternative theory about crystal growth
B. explain how some rocks are not affected by salt
C. simplify the explanation of crystal prying and wedging
D. introduce additional means by which crystals destroy rocks