Which timeline best shows the history of the development of cell theory?

Cell theory states three basic principles: cells are the basic structural and organizational structure of organisms, all living organisms are made up of one or more cells, and cells arise from pre-existing cells.

Several scientists contributed to the development of cell theory are mentioned below as per the timeline:

1590: Hans and Zacharias Janssen invented the first compound microscope.

1665: Robert Hooke observed the first living cell (cork cell).

1668: Francesco Redi disapproved the theory of spontaneous generation.

1674: Anton Van Leeuwenhoek was the first scientist to see and describe bacteria.

1831: Robert Brown discovered the nucleus of the plant cell.

1839: Theodor Schwann and Matthias Jakob Schleiden lead to the development of cell theory.

1855: Rudolf Virchow published "aphorism omnis cellula e cellula" which means that every cell arises from another cell.

1860(s): Lastly, Louis Pasteur disapproved the theory of spontaneous generation  

emerald ash borer

the emerald ash borer is a green buprestid or jewel beetle native to north-eastern asia that feeds on ash species. females lay eggs in bark crevices on ash trees, and larvae feed underneath the bark of ash trees to emerge as adults in one to two years. hope this !

the truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey.