Which is a component of the modern cell theory that was not part of the original cell theory? all organisms are made of cells. all cells are similar in composition and metabolic activities. all cells come from preexisting cells. a cell is the basic unit of structure and function for all living things.

The correct option is this: ALL CELLS ARE SIMILAR IN COMPOSITION AND METABOLIC ACTIVITIES.
The old cell theory is made up of three major parts, which states that:
1. All cells come from pre existing cells.
2.Cells are the basic unit of all living things
3.Cells are the smallest unit of life.
The fact that cells are similar in composition  and metabolic activities had just been recently added to the cell theory.

Could you elaborate?