What is Kamma and rebirth?

Kamma means action, if we do good thing, good result will come back to you and if you do bad thing, bad result will come back to you. It means that the echo of your action will come back to you.

Rebirth- in Buddhism, death is not the end of life, it is merely the end of body we inhabit in this life, but our spirit will still remain and seek out though the seed of attachment , attachment to a new body and new life and reborn again in new life. It  is called rebirth