AP BIOLOGY

Detailed explanation-1: -The first part states that all organisms are made of cells. The second part states that cells are the basic units of life. These parts were based on a conclusion made by Schwann and Matthias Schleiden in 1838, after comparing their observations of plant and animal cells.

Detailed explanation-2: -The three scientists that contributed to the development of cell theory are Matthias Schleiden, Theodor Schwann, and Rudolf Virchow. A component of the cell theory is that all living things are composed of one or more cells.

Detailed explanation-3: -In 1838, German scientist Matthias Schleiden concluded that all plants are made of cells. The next year Theodor Schwann, another German, concluded that all animals were also made of cells.

Detailed explanation-4: -Schwann concluded three things that became vital components of the cell theory. First, Schwann concluded that both plants and animals were composed of cells. Second, these cells have independent lives. Third, these independent lives are subject to the organism’s life.

Detailed explanation-5: -In 1838 Schleiden defined the cell as the basic unit of plant structure, and a year later Schwann defined the cell as the basic unit of animal structure. Schleiden and Schwann articulated their observations as a unified theory-the cell theory-in 1839.