O hidrogênio e o oxigênio são idênticos ou bastante semelhantes entre as narrativas, e os corpos são adaptáveis à variante oxigênio; portanto, é altamente provável que as pessoas possam lidar com o H2O de outra narrativa com um pouco de exposição.
"Do they have water? Oxygen?"
"Their hydrogen is identical to ours. Their oxygen is similar enough
to give them water. We don't know whether we could breathe it.
Carbon seems to be a little different. The metals and so on show
greater divergence."
E depois aprendemos que sim, o oxigênio é compatível:
She shrugged. "Hemoglobin is a classy molecule. Finely tuned to what
it does - take oxygen from the lungs and get it to every cell in the
body. If you give it oxygen that is only a little bit different from
what it's used to, well, it still works - just not as well. It's like
being at high altitude. You get short of breath, woozy, can't think
straight."
...
"...but wait a second, Jules can get along just fine on Arbre air."
"You acclimatize. Your body responds by generating more red blood
cells. After a week or two, you can handle it..."
Quanto a outros gases, o comentário sobre o carbono e os metais pode sugerir que os gases são mais semelhantes entre as narrativas do que os elementos sólidos, mas não há dados para apoiar ou refutar essa teoria.