Final answer:
A substance that is produced by a plant and affects how it grows and develops is called a plant hormone. Plant hormones are chemical substances that control various aspects of plant life, such as flowering, fruit setting, leaf fall, and growth responses.
Step-by-step explanation:
A substance that is produced by a plant and affects how it grows and develops is called a plant hormone. Plant hormones are chemical substances that control various aspects of plant life, such as flowering, fruit setting, leaf fall, and growth responses. They can act in the cell where they are produced or be transported to other parts of the plant. Examples of plant hormones are auxins, cytokinins, gibberellins, ethylene, and abscisic acid.