Concept:A nastic response is a non-directional movement made by an organism in reaction to a stimulus that affects it evenly from all sides.
Explanation:Nastic movements do not depend on the direction of the stimulus, unlike tropisms or tactic movements.
Common nastic stimuli include temperature, humidity, and light intensity.
When light intensity changes, plants show photonasty, such as the opening of flowers in bright light or closing them in darkness.
Stimuli like gravity or chemical substances usually produce directional responses such as gravitropism or chemotropism.
Wound lesion is also not considered a typical nastic stimulus.
Therefore, among the given options, light intensity is the stimulus that most likely triggers a nastic response.
Answer:B. Light intensity