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.
*Hans and Zacharias Janssen had to first develop the microscope before cells could be discovered. Robert Hooke then discovered empty, dead cork cells in tree bark. Anton van Leeuwenhoek discovered the existence of living cells and is sometimes given credit for the microscope. 5. List the three parts of the cell theory.