Final answer:
Not all solid substances on Earth are made of identifiable molecules. A cell in the human body, being a complex structure, is not a substance made of one type of molecule.
Step-by-step explanation:
Molecules as components of matter are common in organic substances and make up most of the oceans and atmosphere. However, not all solid substances on Earth are made of identifiable molecules. Ionic crystals, covalent crystals, and solid metals are examples of substances that are not made of molecules. A cell in the human body, being a complex structure comprised of various types of molecules, is not a substance made of one type of molecule.