Which plant response is characterized by growth towards the source of light?

Phototropism is the response of plants to light, specifically the directional growth toward the light source. This occurs because cells on the darker side of the plant elongate more than those on the side exposed to light, causing the plant to bend toward light. This growth response maximizes light capture for photosynthesis, which is vital for the plant's survival and growth.

In other types of tropisms mentioned, hydrotropism refers to the growth of plant roots towards moisture. Thigmotropism describes growth responses to touch or physical contact, such as climbing plants wrapping around a support. Geotropism, or gravitropism, involves growth in response to gravity, with roots growing downward and stems growing upward. Each of these responses is important for plant adaptation and survival, but only phototropism is characterized by growth towards a light source.