A root hair cell in a plant absorbs minerals that have been dissolved in water. They allow a plant to absorb these minerals by increasing the surface area; this is extremely beneficial to plants that live in dry areas.
The root hair cells are delicate structures on the root of a plant which live only two to three weeks. These cells constantly form at the top of the root of the plant, so as others die, new ones take their place. This allows the root hair coverage to remain the same despite root hairs constantly dying.
The root hairs vary in size, but the lengths range in diameter from about 5 to 17 micrometers and their lengths range from about 80 to 1,500 micrometers. Root hair cells are invisible to the naked eye, but can be seen with the assistance of a microscope. The root hair cells collect nutrients from the water as well as water itself from the soil. They then carry these nutrients and water up to the rest of the plant by way of the plant's roots. The root hairs secrete acids. These acids assist solubilizing minerals into ionic form; this makes the minerals easier to carry and transport through the roots of the plant.