What are the two main types of bone tissue?

The two main types of bone tissue are cortical and cancellous bone. Cortical bone, also known as compact bone, is the dense and hard outer layer of bone that gives it strength and structure. It makes up about 80% of the total bone mass in the human body. This type of bone is essential for supporting weight and providing a shield for the inner structures.

Cancellous bone, on the other hand, is found inside the bones and is characterized by a porous, lattice-like structure. Also referred to as trabecular or spongy bone, it is lighter than cortical bone and contains bone marrow, which plays a critical role in the production of blood cells. The design of cancellous bone serves to absorb shock and stress, making it crucial for overall skeletal function.

While other options like red and yellow marrow or the distinction between dense and spongy do relate to bone composition, they do not represent the primary classifications of bone tissue itself. The correct answer provides a clear and accurate representation of the different structural types of bone tissue.