Which theory suggests that the basic unit of life is the creature or organism, which may be divided into cells?

cell theory

organismal theory

The correct answer is organismal theory.

Simply put, this theory states that the original cell expanded into a whole organism, and that the original cell is equivalent to the whole organism and that the protoplasm is just subdivided and partitioned off by cell walls which are really not complete partitions because the protoplasm of neighboring cells are joined together by plasmodesmata.

This is opposed to the cell theory that states a cell divides into many cells with the original cell being identical to the daughter cells.