Question

The most basic concepts of cell theory are that cells are the basic units of life and that all living things are made of cells. Which answer correctly explains why these concepts are the basis of a theory and not a hypothesis?

Cell theory explains how cells function rather than predicting how they function.
Cell theory has been unchanged for many decades and as a result can be accepted as fact.
Cell theory is a prediction based on observation and not a fully accepted idea.
Cell theory remains largely untested rather than being subject to testing.