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.
Schwann recognized the cell as the basic unit of animal structure. He advanced thecell theory in plants and took the theory over to animals. In 1839 Schwann proposed that all â¦organisms are composed of cells. Together with Matthias Schleiden he formulated the cell theory of life.