Select all the components of cell theory as outlined by schleiden, schwann, and virchow.
a. All cells come from preexisting cells b. The cell is the fundamental unit of life. c. Variation in coll structure is the foundation of evolutionary change. d. A cell is only considered alive if it interacts with another cell.
e. All organisms are made of one or more cells. f. In a multicellular organism, each cell is an organism its own right.