What is the primary function of a plant's root system?

The primary function of a plant's root system is to supply a source of nutrients. Roots play a crucial role in the uptake of water and essential minerals from the soil, which are vital for the plant's growth and development. Through the process of nutrient absorption, roots provide the necessary elements such as nitrogen, phosphorus, and potassium, among others, which are key to various plant functions. This nutrient supply supports overall health and enables the plant to perform essential physiological processes, including growth, reproduction, and resilience against environmental stresses.

The other options focus on different aspects of plant biology. While roots do contribute structurally to the plant, this is not their primary function. Similarly, plants facilitate photosynthesis primarily through their leaves, where sunlight is captured, and glucose is synthesized. Attracting pollinators is mostly related to the flowers of a plant, which rely on reproductive strategies rather than root systems for their function.