Which theory suggests that cells are the basic building blocks of life but don't constitute life itself?
cell theory or organismal theory?

The correct answer would be the organismal theory.

The three main principles of the cell theory are:

The organismal theory was developed as a counter argument towards the cell theory.

One of the principles of this theory states that "cells are the basic building blocks of life but don't constitute life itself". For example, cells removed from a multicellular organism require specific life support systems in order to keep them alive.

its like this, "if i give a plant an unlimited amount of sunlight,then the plant will grow to its largest possible size."

hope it let me know if it does or doesn't =^-^=