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. species of worm used
B. number of trials
C. average number of earthworms in each type of soil
D. soil mosisture

A factor that is changed in response to the change in the other factor in an experiment is called the dependent variable. In an experiment, the independent variable is changed so as to observe the corresponding effect on the dependent variable.

In the given experiment, wet and dry soils were used to observe the effect of soil moisture on earthworms. The effect was observed in terms of a number of earthworms present in each type of soil after a certain duration. Therefore, the average number of earthworms in each soil type was a dependent variable that changed according to the soil moisture (independent variable).