'Natural' in the Bible

Because of this, God gave them over to degrading passions, for their females exchanged the natural relations for those contrary to nature,

and likewise also the males, abandoning the natural relations with the female, were inflamed in their desire toward one another, males with males committing the shameless deed, and receiving in themselves the penalty that was necessary for their error.

For if God did not spare the {natural} branches, neither will he spare you.

For if you were cut off from what is by nature a wild olive tree, and contrary to nature were grafted into a cultivated olive tree, how much more will these who are {natural branches} be grafted into their own olive tree?