Asubstance that cannot be broken down into a simpler substance by ordinary chemical or physical means is a what ?

It is a pure substance

the only liquid elements at standard temperature and pressure are bromine (br) and mercury (hg). although, elements caesium (cs), rubidium (rb), francium (fr) and gallium (ga) become liquid at or just above room temperature.

explanation:

1. they vary with a higher number because boiling is way hotter than melting