Do they have an open or closed circulatory system?
Open, besides Cephalopoda
How does gas exchange take place in phylum mollusca?
Across the body along with lungs or gills
What does the head/foot contain?
feeding, cephalic sensory and locomotor organs.
What does the visceral mass contain?
the digestive, circulatory, resporatory, and reproductive organs.
What is the rasping tongue like organ (not found in bivalves) A ribbon membrane covered with rows of tiny backwards-pointing teeth. Serves to scrape off food and provides a "conveyer belt" transport food toward the disgestive tract?