Bone
Hard connective tissue that forms the skeleton of vertebrates, supporting the body, protecting organs, and producing blood cells in the marrow inside.
Cats purr at 25-150 Hz, and 25-50 Hz happens to match low-frequency vibration therapy used to boost bone density and speed fracture healing. This overlap inspired the hypothesis that cats, who purr even when hurt, may be self-medicating with sound.
0
Humans are born with about 300 bones, but many fuse together during growth, leaving adults with approximately 206.
0