5. How are the criteria for deciding divisions in plants different from the criteria for deciding the sub-groups among animals?

In plants, basic body structure is a major criteria based on which Thallophytes are different from Bryophytes. Apart from this absence or presence of seeds is another important criteria. Gymnosperms and Angiosperms are further segregated based on if seeds are covered or not. It is clear that it is the morphological character which makes the basis for classification of plants. In animals, classification is based on more minute structural variations. So, in place of morphology, cytology forms the basis. Animals are classified based on layers of cells, presence or absence of coelom. Further at higher hierarchy animals are classified based on presence or absence of smaller features, like presence or absence of four legs.