Select the correct answers to the questions from the given options. (Do not copy the questions, write the correct answer only.)
Sunil tried to match the tropic movements in plants with the stimulus they respond to. The tabulation is given below: P. Thigmotropism — Touch Q. Geotropism — Water R. Chemotropism — Chemicals S. Phototropism — Gravity Identify the correct pair:
Topic: Tropisms and their stimuli
Try it
Pick an option and check your answer. The full worked answer is below either way.
Answer
(a) P and R.
Check each pairing against the PREFIX, which always names the stimulus: P. THIGMO- means touch — CORRECT Q. GEO- means earth or gravity, NOT water — wrong (response to water is HYDROtropism) R. CHEMO- means chemicals — CORRECT S. PHOTO- means light, NOT gravity — wrong
So P and R are correct — option (A).
Notice how the question was built: Q and S have had their stimuli SWAPPED with each other’s neighbours. Geotropism should be gravity and phototropism should be light, and the examiner has moved gravity down to S and put water in its place.
THE METHOD: never try to recall the whole table. Read the prefix of each term and check it against the stimulus offered. The Greek root gives you the answer every time — photo light, geo gravity, hydro water, chemo chemicals, thigmo touch.
P and R.