What is a Plant?
Plants belong to the Plantae Kingdom. They are multicellular, have a rigid cell wall, and make their own food. Most plants grow in the soil and use energy from the sun to make their own food. Unlike animals, they can't move on their own and they don't have nervous systems. There are two large categories of plants: non-vascular plants or Bryophytes, like moss; and vascular plants or tracheophytes, like flowers, trees, and grasses.
Bryophytes have no roots, leaves, or stems. Moss and liverworts belong to this group. They are flowerless plants that grow in clumps. They don't have roots. Instead they have thin rootlike growths called rhizoids that help anchor the plant. Because they don't have roots and stems to transport water, mosses and liverworts dry out very quickly, so they are usually found in moist habitats. The only place they don't grow is in salt water.
Unlike bryophytes, tracheophytes have tissues called xylem that transport water and they have food transporting tissues called phloem. Together the xylem and the phloem are called vascular tissue. Vascular plants have roots, stems, and leaves.
Adapted for Growth
Vascular plants, like the daisy, are covered with a waxy layer, or cuticle, that holds in water, and they have pores called stomata that help them take in and let out gasses like carbon dioxide and oxygen. They are covered with a waxy layer, or cuticle, that holds in water, and they have pores called stomata that help them take in and let out gasses like carbon dioxide and oxygen. Their roots take up water and nutrients from the soil and anchor them to the soil. Stems move water and nutrients to the plant's leaves and the leaves capture the sunlight the plant needs for photosynthesis.