Response in Plants

Free sample questions

Response in Plants — sample Biology questions with answers

1. Question 1

   What type of response is shown by the stem of a plant when exposed to light from one direction?

   • APositive phototropism
   • BNegative phototropism
   • CPositive geotropism
   • DHydrotropism

   Answer: A. Positive phototropism

   The stem grows towards light (positive phototropism) to maximise photosynthesis.

2. Question 2

   Which hormone is responsible for phototropism in plants?

   • AGibberellin
   • BAuxin
   • CCytokinin
   • DAbscisic acid

   Answer: B. Auxin

   Auxin is produced at the tip of the shoot and moves to the shaded side, stimulating cell elongation.

3. Question 3

   What is the response of roots to gravity?

   • APositive geotropism (grow downwards)
   • BNegative geotropism (grow upwards)
   • CPositive phototropism
   • DNegative hydrotropism

   Answer: A. Positive geotropism (grow downwards)

   Roots grow towards gravity (positive geotropism) to absorb water and minerals.

4. Question 4

   Why do tendrils of plants like passionfruit wrap around a stick?

   • APhototropism
   • BGeotropism
   • CThigmonasty
   • DThigmotropism

   Answer: D. Thigmotropism

   Thigmotropism is a directional response to touch; tendrils wrap around support.

5. Question 5

   What is the response of roots to high soil moisture?

   • APositive hydrotropism
   • BNegative hydrotropism
   • CPositive geotropism
   • DNegative phototropism

   Answer: A. Positive hydrotropism

   Roots grow towards areas of high moisture to obtain water.