Plant hormones, also known as phytohormones, are chemical signal molecules produced within plant tissues that, in extremely low concentrations, regulate all aspects of plant growth, development, and response to the environment. Unlike animal hormones, which are often produced in specialized glands, plant hormones are synthesized in various cells and can act locally or be transported to other parts of the plant to orchestrate processes such as seed germination, stem elongation, flowering, fruit ripening, and directional growth (tropisms) in response to stimuli like light and gravity. The complex interplay and balance between major hormone groups—including auxins, gibberellins, cytokinins, abscisic acid, and ethylene—are crucial for a plant's ability to adapt and complete its life cycle.