Why did the cephalopod loose its shell? explain two (2) possible evolutionary reasons. briefly discuss the four (4) unifying features of mollusks and explain one major difference between mollusks and worms. how do octopus and squids change color? briefly explain the cause and effect. why do some creatures have weird and bright colors like the pink slug? briefly describe the five (5) major requirements of corals. are they "tourists? " briefly explain the mating ritual of octopus as described in the science articles and lecture slides.