Final Answer:
Eighty percent of bone is made up of cortical bone. Option C is the answer.
Step-by-step explanation:
Cortical bone, also known as compact or dense bone, constitutes the majority of the skeletal system. It forms the outer layer of bones and provides strength, support, and protection. Cortical bone is dense and hard, making it essential for the structural integrity of the skeleton. While spongy bone (Option A) and trabecular bone are also components of bone tissue, they are more prevalent in the interior or ends of long bones. Collagen (Option B) is a protein found in bone, but it does not make up the majority of bone volume. Therefore, the correct answer is option C, as cortical bone accounts for approximately 80% of the total bone mass.
Option C is the answer.