The answer would be
A) synthesis
The H₂O is the formula of the chemical specie while the (s), (l) and (g) tell us the state in which it is present, where s is solid, l is liquid and g is gas.
Hi,
The density is given by the ratio of mass to volume, so the density of the bread is 645g/3450cm3=0.187 g/cm^3.
Hope this helps! If my answer was not clear enough or you’d like further explanation please let me know. Also, English is not my first language, so I’m sorry for any mistakes.
