Evaluate the significance of Anton Van Leeuwenhoek's discovery of live cells in the context of scientific progress.

• A. It was only important for the study of human cells.
• B. It was insignificant as it did not lead to any further discoveries.
• C. It was a minor observation that was quickly overshadowed by other discoveries.
• D. It was a pivotal moment that expanded the understanding of life and laid groundwork for microbiology.

Answer: (D)