LIFE SCIENCE

Detailed explanation-1: -The classical cell theory was proposed by Theodor Schwann in 1839. There are three parts to this theory. The first part states that all organisms are made of cells.

Detailed explanation-2: -Answer and Explanation: Theodor Schwann, an anatomist, and physiologist proved that all animals are made of cells or their structures are the product of cells in 1839. He proposed cell theory and stated that all organisms are composed of cells.

Detailed explanation-3: -Schwann, Theodor (1810–82) A German physiologist who, in collaboration with M. J. Schleiden, proposed the cell theory (and coined the term), according to which all plant and animal tissues are composed of cells, and within an individual organism all the cells are identical (see also VIRCHOW, RUDOLF).

Detailed explanation-4: -In it Schwann declared that “All living things are composed of cells and cell products". He drew three further conclusions about cells, which formed his cell theory or cell doctrine. The first two were correct: The cell is the unit of structure, physiology, and organization in living things.