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

Ex Input:
Passage: Bond lengths are intermediate between covalent single bonds and covalent double bonds. Answer: covalent double bonds

Ex Output:
Bond lengths are intermediate between covalent single bonds and what?

Ex Input:
Passage: Graphs are very useful tools in science because they display data visually. Three commonly used types of graphs are bar graphs, circle graphs, and line graphs. Each type of graph is suitable for a different type of data. Answer: graphs

Ex Output:
Bar, circle, and line are examples of what kind of data visualization?

Ex Input:
Passage: treat genetic disorders. For example, copies of a normal gene might be inserted into a patient with a defective gene. This is called gene therapy . Ideally, it can cure a genetic disorder. Answer: gene therapy

Ex Output:
Inserting copies of normal genes into a patient with defective genes is known as?