There r many kinds of protists also called protozoa.Protists are about 20 times smaller than the dot on this letter i .a type of protist is plasmodia which causes malaria.there floating protists also e.g foraminiferans and diatoms.The main group of protist consists of Amoebas,ciliates,Euglenas annd  parasitic protists.
Bacteria-These r the tiniest ,most abundant,and widespread life forms .It consists of one celled animal and two celled animal.Some take in food from their surroundings while some make food of their own.e.g virus.Diseases  include chicken pox ,measles etc...
Fungi---Mushrooms,toadstools,moulds r the main fungi examples(e.g).Some resembles plants ,but they live in a very different way.FUNGI feed by releasing enzymes(digestive chemical)that break down dead matter.Diseases e.g nappy rash ,ringworm ,athlete;s foot etc. :)