Final answer:
Spiders have an open circulatory system, where hemolymph is circulated through their body cavity. The correct answer is fourth option.
Step-by-step explanation:
Among the options given, spiders have an open circulatory system. This system involves the movement of hemolymph through spaces surrounding the organs rather than blood circulating exclusively within dedicated vessels. Most arthropods, including all spiders, utilize an open circulatory system where the fluid called hemolymph is pumped through their body cavity.
In contrast, dogs and earthworms exhibit a closed circulatory system, where blood is confined within vessels, and it circulates unidirectionally from the heart around the systemic route, then back to the heart. While most mollusks have an open circulatory system, the squid is an exception as it has a closed circulatory system, an adaptation that supports its active lifestyle and rapid movements for catching prey.