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

Problem: Passage: Look at the wheelbarrow in the Figure below . It is used to carry heavy objects. It consists of two simple machines: a lever and a wheel and axle. Effort is applied to the lever by picking up the handles of the wheelbarrow. The lever, in turn, applies upward force to the load. The force is increased by the lever, making the load easier to lift. Effort is applied to the wheel of the wheelbarrow by pushing it over the ground. The rolling wheel turns the axle and increases the force, making it easier to push the load. Answer: lever
Solution: What simple machine works with a wheel and axle in a wheelbarrow?