Answer;
Coelom
Animals with 3 issue layers may be characterized by the presence or absence of a Coelom.
Step-by-step explanation;
- Animals may be characterized by the presence of a coelom, formation of the mouth, and type of cell cleavage during embryonic development.
- Diploblasts contain two germ layers that is the inner endoderm and outer ectoderm, while triploblasts contain three germ layers, that is; endoderm, mesoderm, and ectoderm.
- Triploblasts can be further categorized into those without a coelom called acoelomates, those with a true coelom called eucoelomates, and those with “false” coeloms known as pseudocoelomates.