(A) $T$: $R$.$H$. Whittaker proposed the five-kingdom classification system in $1969$.
$(b)$ $T$: The kingdom Monera is broadly categorized into Archaebacteria and Eubacteria.
$(c)$ $F$: In the taxonomic hierarchy,the order is Class,Order,Family,Genus,Species. Thus,Genus comes before Species.
$(d)$ $T$: Anabaena is a cyanobacterium (blue-green alga),which is a prokaryote and belongs to the kingdom Monera.
$(e)$ $F$: Blue-green algae (cyanobacteria) are prokaryotic organisms and are classified under the kingdom Monera,not Protista.
$(f)$ $T$: All prokaryotic organisms,which lack a defined nucleus and membrane-bound organelles,are placed in the kingdom Monera.