The sequence and number of amino acids is different (each protein has a unique sequence and arrangement of amino acids).
I would say oxygen because respiration is breathing mechanically.
A sudden shift in the tectonic plates of the earth
If we talk about mathematics and the science behind geography, east and west are directions that may represent infinitely. The reason why quantity exist is to measure and create scales on how far an object is from the origin or the point of locus.
These directions can be compared to a line in math which is an endless and limitless progress of points connected without a direction however, incorporating a specific direction could still represent a endless point of west; an endless point to east. Conclusively both are infinite and long unless determined and specified by a continouous measure.
