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You tap a web address. The page appears at once. Where was it before you asked? It was already on a server, a computer far away.

What this track covers

• Networks — computers joined so they can send messages.
• A web address — it names a computer and one of its pages.
• Asking and answering — your phone asks. A server is a computer that answers.
• Search — it reads a list built earlier.
• Cables and radio — two ways a message travels.

This track shows how a web page reaches your phone.