For me it is the fact that our blood contains iron. I earlier used to believe the word stood for some ‘organic element’ since I couldn’t accept we had metal flowing through our supposed carbon-based bodies, till I realized that is where the taste and smell of blood comes from.
Let’s stick with the iron in your hemoglobin for some more weirdness. The body knows iron is hard to uptake, so when you bleed a lot under your skin and get a bruise, the body re-uptakes everything it can. Those color changes as the bruise goes away is part of the synthesis of compounds to get the good stuff back into the body, and send the rest away as waste.
In the other direction, coronaviruses can denature the iron from your hemoglobin. So some covid patients end up with terrible oxygen levels because the virus is dumping iron product in the blood, no longer able to take in oxygen. I am a paramedic and didn’t believe this second one either, but on researching it explained to me why these patients were having so much trouble breathing on low concentration oxygen… the oxygen was there, but the transport system had lost the ability to carry it.
Please tell us more or other things!