Final answer:
An example of a function of a plant stem is to provide structural support, transport nutrients and water, and store food. Stems can be woody or herbaceous and may vary significantly in size and shape, with some even growing underground.
Step-by-step explanation:
An example of a function of a plant stem is to provide support for the plant, holding leaves, flowers, and fruits up to the sun to facilitate photosynthesis. They also serve as conduits for the transport of nutrients and water between the roots and the aerial parts of the plant, along with helping to store food and nutrients.
Plant stems can exhibit a wide range of variations in terms of length and diameter and can be categorized as either herbaceous (soft) or woody. While most stems are above ground, as in the case of trees and most plants, some can grow underground as well; potato tubers are a classic example of such stems.
Overall, stems play a critical role in a plant's growth and survival by fulfilling multiple vital functions, supporting the overall health and functionality of the plant.