Final answer:
Johanson's knee represents a knee bone found in 1974 by American paleoanthropologist Donald Johanson. It is estimated to be over 3 million years old and was part of the famous 40 percent complete skeleton named Lucy.
Step-by-step explanation:
The knee in question represents a knee bone found in 1974 by American paleoanthropologist Donald Johanson. It was part of a skeleton that was about 40 percent complete, which Johanson named Lucy. The knee bone was a significant find as it provided valuable insights into the anatomy and locomotion of early humans.
Johanson's knee bone, along with other bones, was found in Ethiopia during a mapping expedition. It is estimated to be over 3 million years old, making it one of the oldest known hominin specimens. The discovery of Lucy and her knee bone has greatly contributed to our understanding of human evolution.