NEET BIOLOGY

Detailed explanation-1: –First time in the animal kingdom the tissue level of the organization is seen in coelenterates.-Some organ systems are also present in Platyhelminthes.-Arthropods shed a chitinous exoskeleton for allowing the growth and development of the body to give room/space for the growing organs.

Detailed explanation-2: -In Coelenterata and Ctenophora, the arrangement of cells is complex. Here the cells performing similar function are arranged into tissues, hence tissue level of organisation is seen in them.

Detailed explanation-3: -The phylum in which we first see tissue-level organization is Cnidaria, which includes roughly 10, 000 species of animals such as jellyfish and coral. Although very primitive in many ways, cnidarians have cells organized into tissues.

Detailed explanation-4: -Cellular level of body organization.

Detailed explanation-5: -Molluscs exhibit tissue level of organisation.