Why do leaves release water vapor?
Show answer & explanation
Answer: Transpiration pulls nutrients up
Waste removal process — Wrong. Water vapor isn't waste—transpiration is the engine that pulls water containing dissolved nutrients from roots up through xylem to leaves.
Transpiration pulls nutrients up ✓ — Correct! Transpiration is water evaporating from leaf stomata. As water evaporates, it creates negative pressure that pulls water up from roots—like sucking through a straw. This brings dissolved minerals to leaves. Up to 99% of water absorbed is transpired! It's how tall trees get water to top branches!
Excess water must escape — Wrong. Excess water does exit, but transpiration's purpose is creating the pull that transports water and nutrients throughout the plant through cohesion and adhesion.