In 2000, Bob Harmon discovered the best-preserved Tyrannosaurus rex skeleton ever found. The fossilized dinosaur was sticking out of the wall of a canyon in Montana. Many scientists were eager to study the fossils. Dr. Mary Schweitzer got one of the leg bones to analyze. Dr. Schweitzer’s assistant dissolved the bones in acid and discovered that some soft tissue had survived even after 68 million years. The discovery was a shock to the scientific community. No one had ever found such old tissues.

Next, Dr. Schweitzer looked for evidence of proteins in the T. rex tissues. She matched several samples from the fossil to parts of the modern protein collagen. Dr. Schweitzer’s discovery was so revolutionary that very few scientists believed her results. She repeated the experiment several times with great care. Each time she got the same results. In 2017, the scientific community finally accepted that proteins really could survive intact for 68 million years.

Considering the body’s organization from atoms to organ systems, in which level of organization are proteins like collagen? Describe how this level of organization fits into the organization of the whole body.