Plants respond to stimuli by moving their leaves. A specific class of chemical molecules known as plant hormones or phytohormones regulates and coordinates plant growth, development, and reaction to the environment. Plant hormones are made in a specific area of the plant and are relocated to other sections of the body. When a hormone produced in roots is needed, it is translocated to other sections of the plant. Auxins, gibberellins, cytokinin, abscisic acid, and ethylene are the five major types of phytohormones. Auxins, gibberellins, cytokinin, and ethylene are examples of growth promoters, while abscisic acid is an example of growth inhibitor.