Cell Membrane
In 1665, Robert Hooke, an English scientist observed cork under a microscope and noted that it was composed of small units. He called these units cells. Later it was observed that most living things are composed of cells. This led to cell theory. Cell theory is that living things are composed of cells.
A theory is a hypothesis that scientific investigations have shown to be true most of the time. A law is a hypothesis that scientific investigations have shown to be true all of the time. Cell theory is not cell law. …
