Answer: An open circulatory system, where blood is not always confined to vessels.
- A A closed circulatory system identical in plan to the vertebrate system
- B A double circulatory system with separate pulmonary and systemic circuits
- C A purely diffusion-based system lacking a pumping organ altogether
- D An open circulatory system, where blood is not always confined to vessels
Correct answer: D. An open circulatory system, where blood is not always confined to vessels
Explanation: In the cockroach's open circulatory system, the dorsal heart pumps haemolymph into the haemocoel, where it bathes tissues directly rather than remaining confined within vessels throughout its circuit.
The four basic animal tissue types and their core functions: epithelial (covering/lining), connective (support and transport), muscular (movement), and neural (signal conduction).
Concept context
The four basic animal tissue types (epithelial, connective, muscular, neural) and the cockroach as a model organism for organ-system level organisation.