'Natural' in the Bible

For this reason God gave them over to dishonorable passions. For their women exchanged the natural sexual relations for unnatural ones,

and likewise the men also abandoned natural relations with women and were inflamed in their passions for one another. Men committed shameless acts with men and received in themselves the due penalty for their error.

For if God did not spare the natural branches, perhaps he will not spare you.

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