Which device is used to direct the flow of data on a computer network? modem network adapter router port?

Router

Explanation:

A router is one of the most important networking devices. It is used to move network data packets between different networks by directing the flow of the data packets.

A modem, on another hand, is a device for transmitting data over the networking lines (e.g telephone or cable lines) by converting the data into a transmittable format i.e between the digital and analog forms of the data.

A network adapter allows a computer to connect with another device (which may be another computer, a server or similar device) over a connection.

A port is an endpoint to a connection. It allows the connection of networking devices via cables.

Given all of these definitions, it is clear that a router has the function dictated in the question.

Hope this helps!

f7 should open the spelling and grammer dialog box

the difference is right there dont you see it