The curvature movement of plants in response to the stimulus of water is called

1. Analyze the question The question asks for the name of the curvature (growth) movement of a plant in response to water. The key words are "curvature movement" and "water".

2. Explain the concept A tropism is a directional growth response of a plant toward or away from a stimulus. The prefix tells you the stimulus:

• Hydro- = water, so hydrotropism
• Geo- = gravity/earth, so geotropism
• Photo- = light, so phototropism
• Thigmo- = touch/contact, so thigmotropism

3. Step-by-step solution

• The stimulus given is water.
• Option A, hydrotropism, comes from "hydro" (water) and "tropism" (growth movement), so it matches.
• Option B, geotropism, is a response to gravity. Roots grow downward, shoots grow upward.
• Option C, phototropism, is a response to light. Shoots bend toward a light source.
• Option D, thigmotropism, is a response to touch. Climbing plants like yam vines and tendrils coil around supports.

Roots growing toward moist soil is a classic example of hydrotropism (positive hydrotropism).

4. Answer The correct answer is A. hydrotropism.

5. Exam tip Learn the Greek prefixes: hydro = water, geo = earth, photo = light, thigmo = touch, chemo = chemicals. In JAMB tropism questions, the prefix almost always gives away the answer.