The correct option is
None of the Above
Step-by-step explanation:
Both of them have made their own innovations and achievements but collectively they have made one very important discovery (1839): "The Theory of Cells". This theory badges the cell as a basic particle of plants and animals. Schwann and Schleiden were capable to understand that some organism is unicellular, while others are multicellular. Additionally, they found out that the cell nucleus and the membrane refer to the properties of the cell, maintained by representations of various plant and animal tissues.