Uncover the pivotal elements of Cell Theory, a cornerstone of modern biology, through our comprehensive overview. This content is crucial for students, educators, and science enthusiasts eager to grasp the basic units of life. Explore how Schleiden's study of plant tissue led to the recognition of the cell as the structural unit of life, and how Schwann's comparison of animal and plant tissues revealed the cell as the physiological unit. We also delve into Virchow's groundbreaking assertion that all cells originate from pre-existing cells. Learn about the embryonic sac and its role in cellular development, the significance of the nucleus, and the similarities between animal and plant cell structures, including the discovery of polyhedral cells and the observation of cartilage. This resource offers a detailed examination of the three postulates of Cell Theory, elucidating a fundamental concept that asserts all living beings are composed of cells.