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

Passage: Electric current is a continuous flow of electric charges. Current is measured as the amount of charge that flows past a given point in a certain amount of time. The SI unit for electric current is the ampere (A), or amp. Electric current may flow in just one direction, or it may keep reversing direction. Answer: electric current
What is a continuous flow of electric charges called?