When Walt Whitman wrote that he contains “multitudes,” he was probably referring to personal potential. But the 19th-century American poet may just as well have been referring to cells.
Cells are both the smallest biological unit that can survive on their own, as well as the building blocks that construct all living organisms. They contain instructions that can produce over 200 different types — each with their own function. Those instructions contain rules about what kind of cells they can divide into.
Understanding the Basics: What Are Cells?
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The comparison is apt because the youngest cells in a fertilized egg can, indeed, become multitudes — both in terms of numbers and types. They are often referred to as the building blocks of life.
