What is a common use for nitrogen-14?

Baterry.

To breath. We use it to create our energy, without a sufficient source of oxygen we would die in a very short of time because our bodies could not create enough energy and sugar to function.

For counter tops or floors in nice buildings.

Light, heat, sound, cooking, transport, use of computers and televisions.

http is hypertext transfer protocol. it is one of the layer in tcp/ip protocol stack and used most popularly in inernet applictions at user and server agent.