Question

blue green algae have been. included under the kingdom Monera not under plantas?

Answer 1

blue green Algae are unicellular and organism included in plantae Kingdom are multicellular that's why they are included in Kingdom Monera which consists all the organisms who are unicellular and have prokaryotic cellular body

Answer 2

Monera is a kingdom of prokaryotes while organisms of kingdom plantae show definite nucleus, membrane-bound organelles and multicellular body design. Blue green algae are prokaryotes having nucleoid with naked DNA. The cell organelles are also not enclosed with membrane. As they also do not possess multicellular body design, these characters bring them closer to Monera and exclude them from the kingdom Ptantae.