The Fundamental Unit of Life — Science STD 9 — Question

2. R. Virchow.

Explanation:
Rudolf Virchow famously stated Omnis cellula e cellula, i.e., All cells only arise from pre-existing cells. Virchow was a major advocate of the cell theory and published an influential theory that cells arose from each other in a continuous series of generations. He opposed spontaneous generation and carried out experiments in the 1850s to show that nematodes do not arise spontaneously.