Video narration
How does a dry mung bean in damp cotton turn into a seedling with roots and leaves? At first it looks still. As the bean absorbs water, it swells, its coat splits, and a tiny root emerges first. Then the shoot begins to grow. Where does its energy come from? From food packed inside the seed. This store feeds the young plant before its leaves are ready. The cotton holds moisture, while air can still reach the bean. With water, oxygen, and suitable warmth, the embryo inside starts growing. Soil isn't required at this stage, and direct sunlight isn't what starts it. Once the leaves open, the seedling uses light to make its own food. So what starts the change? Water and the right conditions get the mung bean growing: first a root, then a shoot. Only after leaves appear does it make its own food.