The "Lucy" fossil is famous because:

A. the Beatles wrote a song about her
B. she left footprints that were discovered at the same time
C. she was the first australopith ever found
D. her skeleton was 40% intact and undisturbed

D. her skeleton was 40% intact and undisturbed

Explanation:

Lucy was one of the most important discoveries in human evolution. Before the finding of Lucy majorities of the human ancestor bones were not much more than only some bone fragments.

Lucy was the first most complete Australopithecus which was ever found. Lucy was approximately 40% complete fossil. It was found that her brain size was smaller than today's man but she was bipedalism. She was a new species of Australopithecus- Australopithecus afarensis. So the right answer is D.

the answer to your question is tooth decay.