Sorry. If you want you can just remove the parts you didn't make and submit what's left.
But no, 100% originally yours is what you can submit.
i made the sprites...what i didn't made eas the background...if i still cannot submit it like that i will remove it
If you didn't make it, then you can't submit it. I'm sorry, it's a rule.
Better make your own background in the style of existing one - it's not that complex - draw several 8x8 or 16x16 tiles for grass, ground and hills and construct a bg of them.