Carbon dioxide exists naturally in the atmosphere as a result of the earth's carbon cycle. It is also there as a result of man's activities in burning fossil fuels (coal, oil â¦ and natural gas), which releases long-stored carbon dioxide to add to the greenhouse gases already there.
Credit for developing cell theory is usually given to three scientists: Theodor Schwann, Matthias Jakob Schleiden, and Rudolf Virchow. In 1839. I found this answer on examvillâ¦e.com, helped me complete my homework assignment.
This led to the knowledge that all living things were made of cells. In 1855, German physician Rudolph Virchow theorized that all living cells come from other living cells. The contributions of these people led to what we now refer to as the cell theory. This theory states: 1. All living things are made of one or more cells. 2. The cell is the smallest unit of a living organism. 3. Cells come from other cells.