Question

what causes an iron nail to become magnetic when it is rubbed against a permanent magnet over and over again in the same direction? an iron nail is not affected by a permanent magnet. the domains in the iron nail become scrambled. the domains in the iron nail become aligned.

Explanation:

When an iron nail is rubbed against a permanent magnet in the same direction repeatedly, the magnetic domains (small regions with aligned magnetic moments) in the iron nail get aligned. This alignment gives the iron nail magnetic properties. If the domains were scrambled (randomly oriented), the nail would not show net magnetism. And it's a known fact that iron (being a ferromagnetic material) is affected by permanent magnets.

Answer:

The domains in the iron nail become aligned.