Final answer:
The increase in weight and length with over-direction refers to an increase in thickness or girth, which is a result of secondary growth in plants, typically in woody plants like trees and shrubs.
Step-by-step explanation:
The increase in weight and length with over-direction to the previous section suggests secondary growth and is typically associated with an increase in thickness or girth of the stems in plants. In the context of plant biology, one important process is secondary growth, which occurs in the stems and roots of certain plants, resulting in an increase in their thickness. Figure 9.14, referring to a pencil and torque, seems out of place in this biological context, but if analyzing the similar principles in physics, over-direction can cause a mechanical torque that increases displacement, analogous to how overgrowth in a plant section can increase its girth. Secondary growth in stems is usually seen in woody plants such as trees and shrubs, and is the result of activity in the vascular cambium and cork cambium, leading to the production of new vascular tissues and bark. This process results in the plant's increased diameter and is an essential factor in the overall growth of woody plants.