Question

10. A researcher places identical plants in two rooms: one with strong light and one with dim light. After a week, the plants in dim light have longer stems but smaller leaves.
What is the best explanation for this difference?
A. Plants in dim light undergo less photosynthesis, so they grow shorter.
B. Plants in dim light stretch their stems to reach for light, showing phototropism.
C. Plants in strong light lose water more quickly, causing stunted growth.
D. Plants in dim light are genetically different from those in strong light.

Answer 1

B. Plants in dim light stretch their stems to reach for light, showing phototropism (a shade-avoidance/etiolation response where plants elongate stems and reduce leaf expansion to try to reach more light).