👉 In biology, chemotropism is a phenomenon where an organism responds to external cues or stimuli such as chemicals, light, and nutrients by changing its behavior or physiology. This can be described as a biological response that allows an organism to manipulate its environment in ways that it would not do otherwise. Chemotropism can occur at the cellular level, but more often, it is seen in the animal kingdom and involves signaling molecules called chemokines that are released by immune cells or other cells to