Kristan has an outdoor garden where she grows geraniums. One day, she decides to try to grow a geranium inside her house. After a month, she notices that the plant has grown more than those that are outdoors. Kristan begins to wonder why her indoor geranium has grown more than those outdoors. She takes some observations outdoors and indoors and notices that there are differences in humidity, temperature, and light. Based on her observations, Kristan asks the question, "Do temperature variations affect how much geraniums grow?" Which of the following hypotheses might Kristan make to help answer this question?