Which term describes the movement of plants in response to light stimuli?

The term that describes the movement of plants in response to light stimuli is phototropism. This phenomenon occurs when plants grow towards a light source, enabling them to maximize their exposure to sunlight, which is essential for photosynthesis. The growth response is typically facilitated by the unequal distribution of the plant hormone auxin, which is found in higher concentrations on the shaded side of the plant. This concentration gradient causes those cells to elongate more than the cells on the light-exposed side, causing the plant to bend toward the light.

In contrast, geotropism refers to a plant's growth direction in response to gravity, thigmotropism involves growth responses to touch or physical contact, and hydrotropism is the response of plant roots towards moisture. Each of these terms describes different stimuli to which plants respond, but phototropism specifically addresses the plant's adaptive response to light.