Which organisms are called primitive and how are they different from the so-called advanced organisms?

Answer

N/a

Explanation

The organisms having characteristics that came into existence earlier are referred to as primitive and the organisms having characteristic that have come into existence later on are called, advanced. For example unicellular prokaryotic baceria are primitive and multicellular eukaryotic Mammalia are advanced. Likewise, algae are primitive plants and angiosperms and advanced plants. Fishes are primitive vertebrates and birds are advanced vertebrates.