Question 7

New chlorophyll no longer being produced

The change in leaf color during the fall is primarily due to the absence of new chlorophyll production. As the extract explains, in the fall, no new pigment is produced, which allows the other colors present in the leaves to become visible.

A) Chlorophyll in the leaves beginning to break down then

While chlorophyll does break down, this option does not fully capture the reason for the color change. The key factor is that no new chlorophyll is being produced, which is what ultimately leads to the visibility of other pigments.

B) Heat and light causing new pigments to be produced

This option is incorrect because the passage states that in the fall, no new pigment is produced at all. Instead, chlorophyll breakdown reveals pigments that were already present but hidden during the summer.

C) Existing pigments becoming more uniform

This choice is not supported by the text. The passage indicates that existing pigments are revealed due to the breakdown of chlorophyll, rather than becoming more uniform. The colors become visible, not uniform, as chlorophyll disappears.

D) New chlorophyll no longer being produced

This is the correct option because the lack of new chlorophyll production in the fall allows the other pigments in the leaves to be seen clearly for the first time, as highlighted in the extract.

Conclusion

The correct answer, D, accurately reflects the process described in the extract where the absence of new chlorophyll production reveals the pre-existing pigments. The other options either misinterpret the information provided or fail to address the key mechanism behind the color change in leaves during fall. Thus, D is definitive in explaining the phenomenon of changing leaf colors.