Definition: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Muscle tissue consists of cells that can contract, or shorten. Examples include skeletal muscle, which is attached to bones and makes them move. Other types of muscle include cardiac muscle, which makes the heart beat, and smooth muscle, which is found in other internal organs. Answer: cardiac muscle
Output:
What kind of muscle is responsible for making the human heart beat?