Answer:
A. Chelicerates are a group of arthropods
E. Sea urchins are a group of echinoderms
B. Gastropods are a group of mollusks
Step-by-step explanation:
Chelicerates are primitive arthropods having 6 pairs of appendages. 1 oral appendage used for feeding and lack actual mouth parts for chewing up "suck up predigested food". Cephalothorax is the largest and Abdomen contains gills.
Sea urchins are a group of echinoderms as they have spin skin , all marine and found in the bottom of the sea.
Gastropods are the largest and most varied group of molluscs. Gastropod means stomach footed, a typical gastropod is a coiled mass of organs enclosed in a dorsal shell, which rests on the foot having a head ans sensory structures on head and having an operculum.