1) The six kingdoms in the six-kingdom system of classification are Archaebacteria, Eubacteria, Protista, Fungi , Plantae and Animalia
2)The two things that make archaebacteria difficult to study are that archaebacteria lived only in these extreme environments and that we don't know how to feed them for studying them
3) Protista is the most heterogeneous kingdom in terms of morphology
4) The difference between kingdom and domain is that the kingdom is one of the five major groups of living organisms while the domain is one of the three taxonomic categories of living organisms above the kingdom level.
Sorry if i’m late to answer it
I hope it’s correct
