Most arthropods and some mollusks and tunicates have _____ circulatory systems, which means fluid transporting nutrients and oxygen flow directly into internal organs. a. closed b. nonexistent c. open
Arthropoda and molluscs have open circulatory systems - meaning haemolymph (Their equivalent to blood) directly bathes the tissue, and isn't enclosed in blood vessels, as seen in a closed blood system, as in humans for example.
