Given a scientific passage and an answer, generate a question for the given answer.

Let me give you an 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.
The answer to this example can be: A frameshift mutation is a deletion or insertion of one or more of what that changes the reading frame of the base sequence?
Here is why: The science passage defines frame mutation and the main compoment here is nucleotides. Hence the generated question is apt.

OK. solve this:
Passage: The three theories below are essential in Earth science. Each accounts for an enormous amount of data. Each is supported by many lines of evidence. All can be used to make predications. As new evidence arises, any of these theories may need to be altered. But none of these three are likely ever to be disproved. They are accepted by nearly all of the credible scientists in their fields. Answer: theory
Answer:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
In science, what is supported by much evidence, widely accepted by credible scientists, and unlikely to be disproved?