” To which another pundit replied by pointing out that blood doesn’t come in molecules. “
Molecules are the basic building blocks of matter. Molecules consist of combination of atoms. Everything consists of molecules except for the distinct atoms as listed on the periodic chart.
Very good, except that there’s no such thing as a “molecule” of blood. Blood is a heterogeneous substance comprised of many different molecules which are not tied together by molecular bonds. Consider a house. A house is an entity comprised of wood, bricks, nails, wires, pipes, etc. Yet there’s no single component of that entity that can be defined as “house.”