Final answer:
John Dalton was the first to formally theorize that all matter is made up of atoms.
Step-by-step explanation:
John Dalton was the first to formally theorize that all matter is made up of atoms. His atomic theory proposed that atoms are indivisible and indestructible particles that combine in specific ratios to form compounds. Dalton's theory laid the foundation for our understanding of the structure and behavior of matter.
Learn more about John Dalton's atomic theory