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

[EX Q]: 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 A]: Bar, circle, and line are examples of what kind of data visualization?

[EX Q]: Passage: You consist of a great many cells, but like all other organisms, you started life as a single cell. How did you develop from a single cell into an organism with trillions of cells? The answer is cell division. After cells grow to their maximum size, they divide into two new cells. These new cells are small at first, but they grow quickly and eventually divide and produce more new cells. This process keeps repeating in a continuous cycle. Answer: cell division
[EX A]: What process allows an individual to develop from a single cell into an organism with trillions of cells?

[EX Q]: Passage: 22.6 The Hall Effect We have seen effects of a magnetic field on free-moving charges. The magnetic field also affects charges moving in a conductor. One result is the Hall effect, which has important implications and applications. Figure 22.27 shows what happens to charges moving through a conductor in a magnetic field. The field is perpendicular to the electron drift velocity and to the width of the conductor. Note that conventional current is to the right in both parts of the figure. In part (a), electrons carry the current and move to the left. In part (b), positive charges carry the current and move to the right. Moving electrons feel a magnetic force toward one side of the conductor, leaving a net positive charge on the other side. This separation of charge creates a voltage , known as the Hall emf, across the conductor. The creation of a voltage across a current-carrying conductor by a magnetic field is known as the Hall effect, after Edwin Hall, the American physicist who discovered it in 1879. Answer: hall effect
[EX A]:
The creation of a voltage across a current-carrying conductor by a magnetic field is known as what?