Decomposition in the grave is a multi-stage process where a body breaks down due to autolysis (internal cell breakdown) and putrefaction (bacterial and microbial action). Stages include fresh, bloat, active decay, advanced decay, and skeletonization, with the rate heavily influenced by factors like temperature, moisture, and the presence of oxygen. While soft tissues can liquefy in weeks, bones can take hundreds of years to decay fully.Â