AP BIOLOGY

Detailed explanation-1: -In (b) open circulatory systems, a fluid called hemolymph is pumped through a blood vessel that empties into the body cavity. Hemolymph returns to the blood vessel through openings called ostia. Arthropods like this bee and most mollusks have open circulatory systems.

Detailed explanation-2: -As opposed to a closed system, arthropods– including insects, crustaceans, and most mollusks– have an ‘open’ circulatory system.

Detailed explanation-3: -Annelids possess a closed circulatory system.

Detailed explanation-4: -Unlike the closed circulatory system found in vertebrates, insects have an open system lacking arteries and veins. The hemolymph thus flows freely throughout their bodies, lubricating tissues and transporting nutrients and wastes.

Detailed explanation-5: -The species in the phylum Arthropoda have an open circulatory system.