Final answer:
Democritus discovered the concept of atoms and proposed that they are the basic building blocks of all matter. His model suggested that atoms cannot be further divided and changes in matter occur when atoms are reconnected or recombined. He also proposed different varieties of atoms with different properties.
Step-by-step explanation:
Democritus, an early Greek philosopher, suggested that all matter in the universe was made up of tiny, indivisible, solid objects called atoms. His model proposed that atoms are the basic building blocks of all substances and cannot be further divided. He believed that changes in matter occur when atoms are reconnected or recombined in different ways. Democritus also suggested that there were different varieties of atoms with different shapes, sizes, and masses, but only shape, size, and mass differentiated the types of atoms, not characteristics like color and taste.