The two part shell of bivalve molluscs is closed by ______.

Which mollusks have a closed circulatory system?Multiple choice question.BivalvesGastropodsCephalopods

What body region secretes a shell in many mollusk species?

What body region secretes a shell in many mollusk species?Multiple choice question.RadulaFootMantleVisceral mass

What part of a mollusk contains the digestive tract, circulatory organs, excretory organs, and reproductive organs?

Select all of the following that are classes of mollusks.Multiple select question.bivalveschitonscrustaceansgastropodscephalopodspolychaetes