The nature of a nature

In class we said that the need to choose a nature is a nature. From this my question is is there anything that is not a nature? and what is a nature? Is a nature just something you do or is it something that all of humanity does. If it is something all of humanity does then that makes sense. Every civilization since the we evolved with the ability to communicate with one another has tried to define themselves. This means that every culture has other finer subgroups of natures but these are not natures in the sense we talk about in class. Therefore there are many things that are not natures. Any culture specific trait or even more specific, personal trait, is not a nature. The only things to be considered natures would be the things that are significant to every human being. Something that regardless of culture, race or ethnicity everyone does.