Biologists schleiden and schwann would state that

all cells come from other cells

the smallest living unit is the cell

all living things are made up of a cell or cells

all of the above

The correct answer is all of the above options.

Explanation:

The cell theory was presented by Schwann and Schleiden two biologists in 1839. It was a major advancement for the biological studies back then. The cell theory is there were three component of this theory originally-

All living beings are made up of 1 cell or more cells.

Cells form from already existing cells.

The cell is the fundamental unit of structure, function, and organization in organisms.

Thus, The correct answer is all of the above options.