Question

Real organs are absent in

Options

• Mollusca

• Coelenterata

• Arthropoda

• Echinodermata

Answer 1

Coelenterata

Explanation -

Phylum Coelenterata (Cnidaria) has tissue level of body organisation i.e. the cells are grouped together to form tissues, which then perform specific functions. Tissues are not further organised in organs. Therefore, real organs are absent in Coelenterata. On the other hand, in the phyla Arthropoda, Mollusca and Echinodermata, there is organ system level of body organisation i.e. tissues are organised to form organs, which together form an organ system.