we breathe out ...
carbondioxide
what are these?
nostrils
We breathe in ...
oxygen
the ... lung is smaller to give space to the heart
left
this is the ...
respiratory system
what is this?
diaphragm
what are these?
lungs
when we run, our breathing is ...
heavy/fast
what is this?
windpipe/trachea
what is this?
nose
the left lung is smaller to give space to the ...
heart