Water and essential elements are absorbed from soil by which structure?

• A. Leaves
• B. Stems
• C. Roots
• D. Bark

Answer: (C)

Water and essential elements are taken up from soil by the roots. The root surface, especially the fine root hairs, greatly increases contact with the soil solution, where water enters by osmosis and minerals are absorbed through active transport across root cell membranes. Once inside, these nutrients are moved into the vascular system (the xylem) and transported up the plant with the water as it is pulled upward by transpiration. Leaves, stems, and bark don’t serve as the primary entry points for soil water and nutrients—leaves mainly take in carbon dioxide and manage water loss, stems mainly transport, and bark serves as protection—so the roots are the key structure for uptake from soil.