NEET BIOLOGY

Detailed explanation-1: -Plants produce hormones in response to external stimuli. They exhibit this by tropism in which they grow towards sources of water and light. In positive tropism, plants grow in the direction of stimulus and in negative tropism plants grow in the direction opposite to stimulus.

Detailed explanation-2: -An example of external stimuli is your body responding to a medicine. An example of internal stimuli is your vital signs changing due to a change in the body.

Detailed explanation-3: -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-4: -Plants respond to changes in the environment by growing their stems, roots, or leaves toward or away from the stimulus. This response, or behavior, is called a tropism.

Detailed explanation-5: -Thigmotropism is plant growth response to touch. An example of this tropism is the curling of a vine tendril around objects that it touches.