Question

a directional growth of a plant in response to touch. phototropism gravitropism thigmotropism hydrotropism

Explanation:

To solve this, we analyze each option:

• Phototropism: Plant growth in response to light. Eliminate.
• Gravitropism: Plant growth in response to gravity. Eliminate.
• Thigmotropism: Plant growth in response to touch (thigm- relates to touch). This matches the definition.
• Hydrotropism: Plant growth in response to water. Eliminate.

Answer:

C. thigmotropism