Soft tissue survives in dinosaur bones because natural chemical reactions involving iron and dense bone protection lock the proteins in place over millions of years. [1] (https://online.ucpress.edu/abt/article/83/5/298/117017/Preservation-of-Soft-Tissues-in-Dinosaur), [2] (https://newscenter.lbl.gov/2020/02/14/dinosaur-blood-vessels/)