Consider the following.
Terrestrial umbilicals. Scuba divers, e.g., carry bottled atmosphere underwater, taking a bit of our terrestrial environment with us.
Marine umbilicals. Whether on land or under the sea, meanwhile, we always bring along some of the marine environment from which, about 375 million years ago, we vertebrate land-dwellers first emerged. That’s right. We veteran fish-out-of-water types have internalized the seawater that gave us life in the first place. Our blood now comprises part of what is essentially a … Read more