Geotropism refers to growth in response to?

• A. Gravity
• B. Water availability
• C. Light exposure
• D. Temperature

Answer: (A)

Geotropism is the growth response of a plant to gravity. Roots exhibit positive geotropism, growing downward toward gravity, while shoots show negative geotropism, bending upward away from gravity. This sensing happens in the root tip with gravity-detecting cells containing dense plastids (amyloplasts) that settle under gravity and trigger a hormone distribution, mainly auxin, which causes differential growth on the sides of the organ. Because the stimulus here is gravity, this is the correct concept. Other options correspond to different directional cues: plants can bend toward or away from water (hydrotropism), light (phototropism), or respond to temperature (thermotropism).