In the wild, the only tiger subspecies in the wild that have been observed to carry the white color is the Bengal tiger. Even all the white tigers that have been held captive are partly Bengal in subspecies. It is believed that the rare recessive gene that carries the white color comes from Bengal tigers only.
It is difficult to classify viruses as living organisms because they are not made of cells. They only become alive when they find a host i.e. a living cell to live in.ome algae are difficult to classify because they sometimes do not properly fit in one of the kingdoms since they may have characteristics from a few of the kingdoms.
Another classification uses the geometrical shape of their capsid (often a helix or an icosahedron) or the virus's structure (e.g. presence or absence of a lipid envelope). Viruses range in size from about 30 nm to about 450 nm, which means that most of them cannot be seen with light microscopes.