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Question
Who proposed the Cell theory? Explain the main points of this theory.
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Solution
In 1839, M.J. Schleiden and T. Schwann proposed the cell theory. This was further expanded by Virchow in 1858.
The main features of the cell theory as known at present are:
(i) All living organisms are composed of cells. Hence cell is the structural unit of living organisms.
(ii) All cells arise from pre-existing cells of a similar kind by cell division.
(iii) The chemical composition and metabolism of all cells are basically alike.
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