On what basis do taxonomists group animals into phyla?

1.Level of organisation-Either cellular level,tissue level or organ level.

2.Symmetry-Whether the organism is asymmetrical,bilaterally symmetrical or radially symmetrical.

3.Whether the Organism is Diploblastic or Triploblastic.

4.Presence of coelom-acoelomate,pseudocoelomate or acoelomate.

5.Presence of Notocord-Absent, Present for some time in life cycle or present throughout life cycle.