If a plant root gets water on one side and light on the other, which tropisms best explain its direction of growth?
Answer and explanation
Correct answer: Hydrotropism and phototropism
The governing concept is tropic movement, in which a plant part grows directionally in response to an external stimulus. Growth towards water is hydrotropism, while a growth response related to light is phototropism; roots commonly show negative phototropism by growing away from light. Therefore option A identifies the relevant stimulus-based growth responses. Thigmotropism and chemotropism are caused by touch and chemicals, so option B does not match the stated stimuli.
Frequently asked questions
What is the correct answer to this question?
Hydrotropism and phototropism
Why is this the correct answer?
The governing concept is tropic movement, in which a plant part grows directionally in response to an external stimulus. Growth towards water is hydrotropism, while a growth response related to light is phototropism; roots commonly show negative phototropism by growing away from light. Therefore option A identifies the relevant stimulus-based growth responses. Thigmotropism and chemotropism are caused by touch and chemicals, so option B does not match the stated stimuli.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: World of Living. Topic: Control and Coordination.
