AP BIOLOGY

Detailed explanation-1: -Growth in the direction of a stimulus is known as positive tropism, while growth away from a stimulus is known as a negative tropism. Common tropic responses in plants include phototropism, gravitropism, thigmotropism, hydrotropism, thermotropism, and chemotropism.

Detailed explanation-2: -Auxin promotes cell elongation, causing the plant to grow more on the shady side and bend in the direction of the light source.

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: -The plant responds to many types of external stimuli such as light, gravity, weather, and touch. The response of a plant is either positive (grow towards the stimulus) or negative (grow away from the stimulus). For example, phototropism is the plant’s response to stimulus, i.e. sunlight.