Sophia learns that the chromosomes in reproductive cells undergo a process called "crossing over," which allows for greater genetic variation in the reproductive cells. She constructs a partial model, as shown, to illustrate the process of crossing over.

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.