In the year 1850, Rudolf Virchow was studying cells under a microscope, when he observed that cells were dividing and forming new cells. Realizing what he had observed, he understood that living cells reproduce new cells through division. Basing on his conclusion and realization, Virchow proposed that living cells came only from the other living cells.
Tapeworms are known to feed off of their hosts to complete their life cycle. This type of symbiotic relationship is called parasitism. Parasitism is defined as the type of symbiotic relationship wherein only one of the two interacting organisms benefit, at the latter organism's expense. Parasites could either be found inside or outside the host's body. Tapeworms are internal parasites.
