Collagen protein fibers are located in many parts of the body, including the muscles, tendons, ligaments, and bones. Collagen and another protein called elastin are often found together.
<span> (1) All living things are made up of cells, (2) Cells are the smallest units (or most basic building blocks) of life, and (3) All cells come from preexisting cells through the process of cell division. Cells were first observed by the natural philosopher Robert Hooke in 1665. Though many scientists contributed to the understanding of cells, Matthias Schleiden and Theodor Schwann are credited with describing the first two parts of the cell theory in 1839, and Rudolf Virchow with later contributing the third. Today, the cell theory is considered the foundation of biology.</span>
B the cell theory. this is because the cell was so small and darwin saw plant cells using a microscope in the form of a cell that is why the smallest unit of life was called the cell.
