What is the primary function of xylem?

The primary function of xylem is to transport water upward from the roots to the rest of the plant. Xylem consists of specialized vascular tissue that is designed to move water and dissolved minerals absorbed by the roots through the plant to reach stems and leaves, where photosynthesis occurs. This upward movement is essential for maintaining plant health, as water is necessary for various physiological processes, including photosynthesis, nutrient transport, and temperature regulation through transpiration.

In contrast, the other options describe functions associated with different types of plant tissue. The transport of nutrients from leaves to roots is primarily facilitated by phloem, not xylem. Carbohydrate storage is typically managed by other tissues, such as parenchyma, rather than xylem. Lastly, gas exchange is performed by stomata and is associated with leaf structures, taking place in the epidermis and mesophyll rather than in the xylem tissue itself. Thus, the correct answer accurately reflects the specialized role of xylem in plant physiology.