if a substance has a higher density than another substance , then the molecules in the substance will be closer than those of the other substance
density is not multi_dimensional_quantity. metals is stronger_than_others. density is multi_dimensional_quantity. cellular_growth_factor is not molecular_material. density is not tangible_physical_quantity. substance is substance. epidermal_growth_factor_molecule is not epidermal_growth_factor. growth_factor_molecule is not cellular_growth_factor. epidermal_growth_factor_molecule is not growth_factor_molecule. cellular_growth_factor is molecular_material.