What function does the stem serve in a plant?

The stem of a plant primarily serves to support the leaves and transports water and nutrients throughout the plant. The structure of the stem allows it to provide stability and elevation to the leaves, which are critical for photosynthesis, as they need to be positioned to capture sunlight effectively. Additionally, the stem houses vascular tissues—specifically xylem and phloem—that facilitate the movement of water and nutrients from the roots to the leaves and other parts of the plant. This function is essential for maintaining the plant's health and promoting growth. In essence, the functioning of the stem is central to the overall physiological processes of plants, making it crucial for their survival and development.