SAT Subject Biology Practice Question 307: Answer and Explanation
17. Tropisms refer to movements made by plants toward or away from certain stimuli. "Positive" tropisms refer specifically to movements toward a stimulus, whereas "negative" tropisms refer to movements made away from a stimulus.
A plant growing on the shady side of a building bends around the corner of the building toward the sunlight. This is an example of
A. negative geotropism
B. negative phototropism
C. positive phototropism
D. positive hydrotropism
E. negative hydrotropism
Correct Answer: C
C The prefix photo refers to light; because the plant is growing toward light we can eliminate choices A, D, and E. "Positive" means growing toward, so choice B can be eliminated.