Plants come from seeds. A seed must have water, the right temperature and a good location, normally in soil, before it will germinate and begin growing into a plant.
Young plants use food stored in the seed until they can create their own using photosynthesis. The seedling grows roots to help anchor it into the ground and absorb water and nutrients from the soil. The stem grows upward pushing its leaves toward sunlight at the surface, and eventually, a shoot emerges from the soil, ending the germination phase. A plant that continues to get water, warmth, light and nutrients will continue to grow.