Which of the following characters for echinodermata are correct? (i) These animals have an exoskeleton of calcareous ossicles. (ii) All are marine with organ-system level of organisation. (iii) Digestive system is complete with mouth on the dorsal side and anus on the ventral side. (iv) Water canal system present which helps in locomotion, capture and transport of food and respiration. (v) They are monoecious, fertilisation is usually external. (vi) Development is indirect with free-swimming larva.