1, plants have the ability of photosynthesis-that is, they can use light energy and chlorophyll that animals don't have, use water, inorganic salts and carbon dioxide for photosynthesis, release oxygen, and produce glucose, an energy-rich substance for plants to use. Plant chlorophyll contains magnesium. Plant cells have obvious cell walls and nuclei, and the cell walls are composed of glucose polymer-cellulose.

2. The ancestors of all plants are unicellular non-photosynthetic organisms, and they devour photosynthetic bacteria, forming a mutually beneficial relationship: photosynthetic bacteria live in plant cells (the so-called endogenous phenomenon). Finally, bacteria become chloroplasts, which are organelles that exist in all plants but cannot survive independently. Most plants belong to angiosperms, which are flowering plants, including many kinds of trees. Plant respiration is mainly carried out in mitochondria of cells; Photosynthesis takes place in the chloroplast of cells.

3. The photosynthesis of green plants is the most common and largest reaction process on the earth, which plays an important role in organic matter synthesis, solar energy accumulation, air purification, maintaining the stability of oxygen content and carbon cycle in the atmosphere, and is the basis of agricultural production, which is of great significance in theory and practice. According to calculation, green plants all over the world can produce about 400 million tons of protein, carbohydrates and fat every day, and at the same time release nearly 500 million tons of oxygen into the air, providing sufficient food and oxygen for people and animals.