Question

The movement of the sunflower plant is a response to which type of stimulus?

• A. Gravity
• B. Chemical
• C. Day or Night
• D. Water

Hint:

Sunflowers respond to light stimulus (day/night), not to gravity or chemicals.

Answer 1

The Correct Option is C

The movement of the sunflower plant, specifically its heliotropic behavior, is a response to light, which correlates to the changes between day and night. This natural behavior allows the sunflower to maximize its exposure to sunlight for optimal photosynthesis during the day. While gravity, chemical signals, and water are important factors in plant growth and movement, the characteristic tracking movement of sunflowers from east to west during the course of a day is primarily a response to sunlight, which coincides with the day-night cycle.

Stimulus	Response
Gravity	Plant roots growing downward
Chemical	Response to nutrients or toxins
Day or Night	Heliotropism in sunflowers
Water	Root growth towards moisture

Hence, the movement of sunflower plants is primarily a response to the "Day or Night" stimulus, reflecting its adaptation to light changes during these periods.