Teacher: Given a scientific passage and an answer, generate a question for the given answer.
Teacher: Now, understand the problem? If you are still confused, see the following example:
Passage: A frameshift mutation is a deletion or insertion of one or more nucleotides that changes the reading frame of the base sequence. Deletions remove nucleotides, and insertions add nucleotides. Consider the following sequence of bases in RNA:. Answer: nucleotides.
Solution: A frameshift mutation is a deletion or insertion of one or more of what that changes the reading frame of the base sequence?
Reason: The science passage defines frame mutation and the main compoment here is nucleotides. Hence the generated question is apt.

Now, solve this instance: Passage: Scientists refer to the vertical extent of ocean water as the water column . Two main zones based on depth of water are the photic zone and aphotic zone. The photic zone is the top 200 meters of water. The aphotic zone is water deeper than 200 meters. The deeper you go, the darker the water gets. That's because sunlight cannot penetrate very far under water. Sunlight is needed for photosynthesis. So the depth of water determines whether photosynthesis is possible. There is enough sunlight for photosynthesis only in the photic zone. Answer: water column
Student:
What is the vertical extent of ocean water called?