Final answer:
Cephalopods have a closed circulatory system that supports their active lifestyle and complex behavior by efficiently transporting gases, nutrients, and waste, which is necessary for meeting their higher metabolic demands.
Step-by-step explanation:
A change in the circulatory system organization in cephalopods, such as squids, supports their complicated body designs by enabling them to meet higher metabolic demands needed for their active lifestyle, which is characterized by rapid movement for active hunting, and sophisticated behaviors. Unlike other mollusks with more simple open circulatory systems, cephalopods have evolved a closed circulatory system, where the blood is contained within vessels. This adaptation allows for more efficient transport of gases, nutrients, and waste throughout the body, meeting the demands of their larger size and more active life, as they must quickly process and deliver these resources to support their activities.
Therefore, the correct answer to how a change in the circulatory system supports the body designs in cephalopods compared to other mollusks is b) It supports higher metabolic demands required for active hunting and complex behavior in cephalopods.