How important is the presence of air bladder in Pisces?

4 What are the peculiar features that you find in parasitic platyhelminthes? 5 What are the reasons that you can think of for the arthropods to constitute the largest group of the animal kingdom? 7 What are the modifications that are observed in birds that help them fly? 8 In which of the following is Segmentation in the body first observed:(a) Platyhelminthes (b) Aschelminthes (c) Annelida (d) Arthropoda.