Question

Which of the following is/are correct?
(i) Sponges : Cellular level of organization
(ii) Cnidaria : Tissue level of organization
(iii) Platyhelminthes : Organ level of organization
(iv) Annelids, Arthropods, Molluscs, Echinoderms and Chordates : Organ system level of organization

• A. All are correct
• B. (ii) and (iv) only
• C. (ii) and (iii) only
• D. (i) and (ii) only

Answer 1

The correct option is A All are correct

Animals show four different grades of organization:
(i) Cellular grade is the characteristic of sponges.
(ii) Tissue grade appears in Cnidaria.
(iii) Organ level is exhibited by members of Platyhelminthes and other higher phyla where tissues are grouped together to form organs.
(iv) Organ system level of organisation is found in Annelids, Arthropods, Molluscs, Echinoderms and Chordates.