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

Example input: 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.
Example output: A frameshift mutation is a deletion or insertion of one or more of what that changes the reading frame of the base sequence?
Example explanation: The science passage defines frame mutation and the main compoment here is nucleotides. Hence the generated question is apt.
Q: Passage: Since the early 1990s, astronomers have discovered other solar systems. A solar system has one or more planets orbiting one or more stars. We call these planets "extrasolar planets," or exoplanets . They are called exoplanets because they orbit a star other than the Sun. As of April 2014, more than 4,600 exoplanets have been found, with 1706 confirmed. The rate of discovery is increasing rapidly! You can check out how many we have found at http://planetquest. jpl. nasa. gov/ . Answer: solar system
A:
What do you call a system that has one or more planets orbiting one or more stars?