Final answer:
Spongy bone has complex shapes and contains a varying amount of spongy and compact bone. It consists of a lattice-like network of matrix spikes called trabeculae, and its spaces contain red marrow.
Step-by-step explanation:
Spongy bone has complex shapes and varies in the amounts of spongy and compact bone it contains. Unlike compact bone, spongy bone is not arranged in concentric circles. Instead, it consists of a lattice-like network of matrix spikes called trabeculae. The spaces in spongy bone contain red marrow, where hematopoiesis occurs.