logy ACTIVITY PROPER DIRECTION: Identify the scientists who made the given contributions. Write their names in the crossword puzzle. Across: 2. Concluded that all plant are compos of CELL 3. Proposed that all living things are composed of Cells 4. cells originated from division of pre- existing cells. Down: 1. He claimed that motility is the quality a life. 5. Proved that all cells arise from prexistin cells 6. Began the scientific study of cell in the 17th century.​