Given a scientific passage and an answer, generate a question for the given answer.
One example is below.
Q: 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.
A: A frameshift mutation is a deletion or insertion of one or more of what that changes the reading frame of the base sequence?
Rationale: The science passage defines frame mutation and the main compoment here is nucleotides. Hence the generated question is apt.
Q: Passage: The heart is a muscular organ in the chest that consists mainly of cardiac muscle. It pumps blood through blood vessels by repeated, rhythmic contractions. Blood flows through four chambers of the heart when it beats. Heartbeat is controlled by electrical signals from special cells within the heart called the pacemaker. Answer: cardiac muscle
A:
What type of muscle makes up most of the heart?