Which is more efficient for networking traffic a switch or a hub Why?

A switch. Each port has a separate path to each of the other ports on the switch. On a hub, all the ports are tied together into 1 single port. Think of a switch as an 4 lane freeway with 8 entrances and exits; a hub is a one lane highway with the same 8 entrances and exits. It can pass data from only one port to another port- switch can connect 4 ports to the other 4 ports (or 8 to 8 or 16 to 16, you get the idea)

A switch is quite a bit more complicated AND is generally more expensive: between 20% and 300% more than a hub with the same number of ports BUT it's very useful on a busy network (business especially.)