Question

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

Answer 1

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Organisms with simple cellular structure and no division of labour are called

primitive.

Advanced organisms, like mammals have millions of cells and there are different organs and organ system for different biological functions.

Answer 2

Primitive organisms are those which have ancient body designs and have not changed much. They have simpler body design and are also called lower organisms. On the other land, the organisms that have acquired more complex structure and body design relatively recently are called advanced organisms