Roots

THE ROOTS BELOW GROUND

We'll start at the bottom with the roots. These structures are designed to pull water and minerals from whatever material the plant sits on. For water plants, the roots may be in the water. For traditional trees, the roots go deep into the soil. There are even plants called epiphytes that live in trees and their root system clings to branches. Humans often capitalize on the roots of plants for food.
Carrots are just one big orange root.

Root systems also provide support for plants in the form of an anchor in the soil. If the wind blows hard, those roots keep the plant from falling over. Some plant species have roots above ground that provide support for the entire plant. Roots are further broken down into the primary root and lateral roots that each has apical meristem at their tips. Root hairs are also a common structure on roots. They make the roots look fuzzy and help in the absorption of water and nutrients.

http://www.biology4kids.com/files/plants_structure.html