AP BIOLOGY

Detailed explanation-1: -The idea that new cells arose from pre-existing cells in both diseased and healthy tissue was not original. Robert Remak, a neuroscientist, had already come to this conclusion in 1852, though his publication went largely unnoticed. Virchow also discovered that bones and connective tissue were composed of cells.

Detailed explanation-2: -The third part, which asserts that cells come from preexisting cells that have multiplied, was described by Rudolf Virchow in 1858, when he stated omnis cellula e cellula (all cells come from cells).

Detailed explanation-3: -In 1858 he published Cellular Pathology, a groundbreaking book of 20 lectures he had given at the university, which laid the foundations of modern pathology and indeed of modern medical theory. Simply put, Virchow established that all diseases can be traced to cells.