A student is conducting an experiment to determine what type of soil earthworms prefer, wet or dry. Ten earthworms are released into a cardboard box that contains dry soil on one side and wet soil on the other. Over 24 hours, the student records the number of earthworms on both sides every hour. What component of the above experiment is the dependent variable? A) soil moisture B) number of trials C) average number of earthworms in each type of soil D) species of worm used