Final answer:
The primary anatomical and functional unit of cancellous bone is the trabeculae, which forms the interconnected network of bony struts that make up cancellous bone.
Step-by-step explanation:
The primary anatomical and functional unit of cancellous bone is the trabeculae. Cancellous bone, also known as spongy or trabecular bone, is characterized by its porous and honeycomb-like structure. The trabeculae are the interconnected network of bony struts that make up cancellous bone and provide support and strength to the bone.