One function of the stem is?

One function of the stem can be that transports water from the roots to the leaves of the plants.

These stems are vital and needed for active transportation of the water molecules either for the production of food for the plants or to supply sufficient moisture and hydration for other cellular activities in autotrophs however, the most essential function of the stem is also to support the photosynthetic mechanism of plants which is to make their own food and obtain energy from it called photosynthesis which needs sunlight, carbon, and water.