Live~NRGY

https://en.wikipedia.org/wiki/Side_chain

…”The placeholder R is often used as a generic placeholder for alkyl (saturated hydrocarbon) group side chains in chemical structure diagrams. To indicate other non-carbon groups in structure diagrams, X, Y, or Z are often used.”…

Come come now, whether ‘R or XYZ or substituent…

It is all the same where STP is concerned

My Dear Watson…

It’s all Thermodynamics

Function Changes because of

F=ma and…(let you guess)

Ditto for any other apron holders

See simple

Pass the Slice of Pi please