Sub-cellular and Acellular particles:

According to the first principle of the cell theory, all organisms are composed of one or more cells. The Discovery of viruses, prions, and Viroids claims that the statement is not so universal. They are not composed of cells, rather they are sub-cellular or acellular particles that do not run any mechanism inside them, but they show some characteristi9cs of living organisms i.e., they can increase in number and can transmit characters to the next generations.