Why would scientist feel the need to add on to the Cell Theory?

his is crucial for us understanding biology because cells form the basis of all life. We can have unicellular organisms, like bacteria, like yeasts. [And] cell division, the division of a cell from one, to two, to four, forms the basis of growth and development of all living things.

Explanation:

yes, because even though a theory has a  lot of evidence to support it, it is not always true