Video narration
What is your body made of at its smallest living scale? Look closer, and the familiar shape of you gives way to a world too small to see: cells, tiny living units that make up your body. In that unseen world, a cell is not just a tiny shape; it is a living unit. Follow one, and you can see what that means: it takes in what it needs, uses energy, and responds to its surroundings. Now rewind. In the seventeenth century, Robert Hooke examined a piece of cork through a microscope. He saw tiny compartments in the cork and named them cells. But the cork compartments Hooke called cells were dead, not living cells. Your body is made of cells-tiny living units. Hooke's look at cork gave them their name, though the compartments he saw were dead.