Question 2

Chlorophyll in the leaves beginning to break down then

The breakdown of chlorophyll in leaves is the primary factor that leads to the change in color during the fall. As chlorophyll diminishes, the other pigments that were previously masked by the vibrant green become visible.

A) Chlorophyll in the leaves beginning to break down then

This option is correct as the passage states that chlorophyll breaks down in the fall, revealing the other colors that were always present but hidden. The gradual breakdown of chlorophyll allows for the splotches of yellow and red to emerge, marking the change in leaf color.

B) Heat and light causing new pigments to be produced

This option is incorrect. The passage mentions that during the fall, no new pigment is produced; rather, the existing pigments become visible as chlorophyll breaks down. Therefore, heat and light are not responsible for the production of new pigments in the fall.

C) Existing pigments becoming more uniform

This option is also incorrect. The passage does not suggest that existing pigments become more uniform; instead, it explains that the breakdown of chlorophyll allows the variety of colors that were always present to be seen. The change in color is due to the visibility of these pigments rather than their uniformity.

D) New chlorophyll no longer being produced

While this option may seem relevant, it is incorrect in the context of the question. The passage indicates that chlorophyll is not being replaced in the fall, which contributes to the color change, but it is the breakdown of chlorophyll that is the direct cause of the visible color change in leaves.

Conclusion

In summary, the primary reason for the change in leaf color during the fall is the breakdown of chlorophyll, which allows other pigments to show through. Options B, C, and D do not accurately reflect the mechanism described in the passage, making A the only correct choice. Thus, A directly addresses the cause of the color change as highlighted in the extract.