Answer:
This question lacks options, the options are;
A. All cells have a cell wall.
B. All cells arise from pre-existing cells.
C. All cells are capable of photoshynthesis.
D. All cells can develop into any other type of cell.
The answer is B.
Explanation:
The widely accepted universal cell theory is known to be contributed to by three scientists viz: Matthias Schleiden, Theodor Schwann and Rudolph Virchow.
As rightly stated in this question, Botanist Mathias Schleiden and Zoologist Theodor Schwann proposed that plants and animals are made up of cells in the year 1838 and 1839 respectively. However, in 1855, biologist Rudolph Virchow expanded the cell theory by adding that all living things are composed of cells and that these cells arise from pre-existing cells.
The collaboration of these three scientists brought about the cell theory that states:
* Cells are the basic unit of all living things.
* All living things are made up of one or more cells.
* All cells arise from pre-existing cells.
