Given a scientific passage and an answer, generate a question for the given answer.
One 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 is here: A frameshift mutation is a deletion or insertion of one or more of what that changes the reading frame of the base sequence?
Explanation: The science passage defines frame mutation and the main compoment here is nucleotides. Hence the generated question is apt.

Now, solve this: Passage: You could argue that oxygen is one of the most important, if not THE most important molecule necessary for life. However, oxygen is essentially just a waste product of the light reactions of photosynthesis. It is a "leftover" from a necessary part of the process. All the oxygen that is necessary to maintain most forms of life just happens to be released from the plant during this process. Answer: photosynthesis
Solution:
Oxygen is essentially just a waste product of the light reactions of what?