was introduced in 1838 by 3 scientists named Matthias Schleiden, Theodor Schwann, Matthias Schleiden. The cell theory is composed of 3 sections

1. Cells are the smallest thing in life

2. They make up everything

3. All cells come form existing cells ( they reproduce into more cells)

         Differences between multicellular and unicellular organisms

The difference between the multicellular and the unicellular is that a unicellular contains no nucleus and only has one cell therefore the name uni celler and the multicellular contains more than 1 cell and has a nucleus.