[u]Tongue and mouth/nose breathing[/u]
?Mouth-breathing? Try pressing tongue well forward in mouth as if saying the letter ‘L’. It seems to make it much easier to nose-breath.
The habitual position for our tongue to rest in our mouth makes a difference to the space at the back of the throat and other muscles in the jaw and neck so it is an important [u]habit[/u] to explore and optimize not just take for granted that where the tongue is resting usually is the ideal place for it to be.
This seems to be just a habit like our posture. With awareness it can be improved.