NEET BIOLOGY

Detailed explanation-1: -One important light response in plants is phototropism, which involves growth toward-or away from-a light source. Positive phototropism is growth towards a light source; negative phototropism is growth away from light.

Detailed explanation-2: -Some common plant stimuli include light, gravity, water, movement of the sun, and touch. The naming of the tropism is associated with the stimulus. For example, the movement of plant roots towards water is called hydrotropism.

Detailed explanation-3: -Phototropism, a reaction to light, causes the plant to bend toward the light source (see Essential Processes, Auxins). Thigmotropism, a reaction to touch, causes parts of the plant to thicken or coil as they touch or are touched by environmental entities.

Detailed explanation-4: -Phototropism is the movement of plant parts in response to light. Thus, the stimulus for phototropism is “Light”.