Question

On the basis of the origin of the mouth, animals have been categorized into...

Answer 1

Hint: A germ layer is an essential layer of cells that structures during early-stage improvement. The three germ layers invertebrate creatures are especially articulated; notwithstanding, all eumetazoans produce a few essential germ layers.

Complete answer:
Some creatures, like cnidarians, have two germ layers (ectoderm and endoderm), making them diploblastic. Different creatures, such as bilaterians, produce a third layer (the mesoderm) between these two layers, causing them to be triploblastic. Through the interaction of organogenesis, germ layers eventually produce the entirety of a creature's tissues and organs. Creatures have been classified into Protostomia and Deuterostomia based on the source of their mouth.
Protostomia is the clade of creatures once thought to be described by the arrangement of the organic entity's mouth before its rear-end during undeveloped turn of events. This nature has since been found to be a very important factor among Protostomia's individuals, albeit the opposite is ordinarily valid for another clade, Deuterostomia. Some instances of protostomes are arthropods, molluscs.
Deuterostomia are creatures regularly described by their rear-end shaping before their mouth during undeveloped turn of events. The gathering's sister clade is Protostomia, creatures whose stomach related lot improvement is more changed. A few instances of deuterostomes incorporate vertebrates, ocean stars, and crinoids.

Note:
In deuterostomes, the developing organism's first opening (the blastopore) becomes the back end, while the mouth is framed at a later stage. This was originally the gathering's distinguishing feature, but deuterostomes have since been discovered among protostomes as well. This group is known as enterocoelomates due to the fact that their coelom is created by enteroceles.