The purpose of a Truss Bridge is to distribute weight so that it is light than the force applied. to make the bridge heavier.

The purpose of a truss bridge is to distribute weight efficiently, making it *stronger* than it would be otherwise for a given amount of material. It does not make the bridge heavier; in fact, trusses are used to create strong yet relatively lightweight structures. So the first statement is closer to correct, but should say stronger, not lighter.