Final answer:
Spongy bone features trabeculae, which are projections in a lattice-like matrix providing strength and lightness to bone, and contain spaces often filled with red bone marrow.
Step-by-step explanation:
The spongy bone, also known as cancellous bone, is less dense than compact bone and has an important structural component called trabeculae. These trabeculae are spike-like projections in the lattice-like matrix that compose the spongy bone. Unlike compact bone, which is organized into rings called osteons, the trabeculae in spongy bone are not arranged concentrically but instead form along lines of stress within the bone. This structure provides strength and lightness, making it easier for muscles to move the bones.
Additionally, the spaces within this lattice structure are often filled with red bone marrow, crucial for hemopoiesis—the production of blood cells.