Michelle and Juan are working on a science project. They take a large glass jar, fill it with some damp paper towels, and then with seeds. They place this jar near a window. After a few days, they see that the seeds germinate and produce stems growing upward. Next, they moisten the towels again and lay down the jar on its side. What are they most likely to observe about the stems after turning the jar on its side?
A: Grow sideways in their new position
B: Start growing downward in their new position
C: Stop growing more than they have already grown
D: Start growing upward in their new position