i can give an example-nanobacteria: through electron micrographs, some scientists thought that the structures they are looking at is bacterium and it is nano sized. so, they concluded the existence of nano bacteria. but, when many other scientists started studying about it, they found that they are not bacteria but are crystals of some inorganic compound!!i hope this helps.
nano bacteria donot exist, but nano sized bacteria do exist--they are nothing but some dormant stages of bacteria.
