““A plant can be pulled in many directions at once. Sunlight hitting a plant at an angle caises it to bend toward the rays, while the sinking statoliths within the plant's bending branches tell it to straighten up. These often conflicting signals enable a plant to situate itself in a position that is optimal for its environment. The tendrils of a vine, searching for a support to grab onto, will be attracted to the shade of the neighboring fence, and gravity will enable the vine to rapidly twirl around it. A plant on a windowsill will be pulled by the light and grow to one side, toward the sunny part of the sill, while the force of gravity will influence it to grow up at the same time. The smell of the tomato will pull Cuscuta to the side, while gravitropism will push it to keep growing upward. Just like Newtonian physics, the position of any part of the plant can be described as a sum of the force vectors acting upon it that tell a plant both where it is and which direction to grow.””
