Question

A scientist follows this procedure to test whether plants have been performing photosynthesis.

Place Plant X in a dark closet and Plant Y on a sunny windowsill.
Wait several days, then remove a leaf from each plant.
Boil leaves in alcohol to remove the chlorophyll.
Add a chemical indicator that detects sugars. (Dark purple = sugars are present; dark orange = sugars are not present)
What results will the scientist most likely obtain when placing drops of the indicator on the leaves?

Plant X: dark purple
Plant Y: dark purple
Plant X: dark orange
Plant Y: dark purple
Plant X: dark orange
Plant Y: dark orange
Plant X: dark purple
Plant Y: dark orange
A B C OR D

Answer 1

B — Plant X: dark orange; Plant Y: dark purple.

Reason: Photosynthesis requires light, so the plant in the dark won't make sugars (no color change), while the sun-exposed plant will produce sugars (indicator turns dark purple).