Orcs

Ok i know that orcs were made from elves in the very begginning, by morgoth. Yet how can orcs be so weak whire elves are so strong? Is it because they were a mockery of elves? ALso do they breed or are they spawned? cuz it seems that the darks lords can whistle up huge numbers.

When you say that orcs are weak do you mean physical muscle strength? In that matter, the bulk of orcs(not the mountain goblins) aren't weak. Take a look at gollum, they have strength, they would have to for the work they do. You hear Sam describing Gollum as strong when he's fighting Gollum in Shelob's cave. Gollum is quite similar to orcs, self-loathing, while hating everything and everyone else, just filled with Hate. The orcs were from elves, I think.

OK, well there are a lot of orcs, i think they are immortal also, but that doesnt seem right. Also, are they tireless like elves?

Do we have any evidence that orcs AREN'T immortal? That they don't live forever? I say we don't. They just die quite often, and soonly, because they are the grunts, because they are sent to the slaughter, to get things done, and who cares if they die.
Are they tireless? Well, they can go long distances, You see the party of Uruk's, Goblins, and Orcs traveling with hobbits go for a very long time, kept up with the orc-draught, probably their equivalent of the elvish Lembas Bread. Tireless? I don't think even the elves are tireless, as if they never tire, They still need sustinence. They are very tough, and very resilient, but I don't think they could run forever on empty.