The graph shows the results of an experiment that investigated the effect of light intensity on the rate of photosynthesis.
What are the labels for the x-axis and the y-axis?
▶️ Answer/Explanation
Ans: A
In experiments on photosynthesis, the x-axis typically represents the independent variable, which is light intensity (as it is manipulated). The y-axis represents the dependent variable, which is the rate of photosynthesis (measured outcome).
Option A correctly matches these labels, while the other options misplace them. Thus, the correct answer is A (Light intensity on x-axis, Rate of photosynthesis on y-axis).
Some variegated leaves have white parts and green parts. A plant with variegated leaves has the starch removed from its leaves by placing it in a dark cupboard for 48 hours. Black paper is then fixed on one leaf as shown and the plant is exposed to light. After 24 hours, which part of the leaf contains starch?
▶️ Answer/Explanation
Ans: D
The experiment involves destarching the leaves (removing stored starch) by keeping the plant in the dark for 48 hours. After exposing it to light for 24 hours with black paper covering part of the leaf:
- Green parts (exposed to light): Contain chlorophyll and perform photosynthesis, producing starch (e.g., part D).
- White parts: Lack chlorophyll, so no starch is produced even with light.
- Covered parts (black paper): No light = no photosynthesis, so no starch.
Thus, only the green, uncovered area (D) contains starch after the experiment.