Headscratchers / The Octonauts

• How does Professor Inkling, being an octopus, breathe in the ship?
• Why Peso from all the crew is even an octonaut? He clearly only knows how to bandage wounds, but he is ignorant at sea biology from many creatures. Despite he has saving the day in a few times, like control the Octopod, with the Belugas and helping Barnacles with his claustrophobia, he received help more of them, he is also the member who gets in troubles more. And Barnacles says to his mom that Peso is very valious, probably to make them proud despite Peso's clumsiness.
• The Octonauts seem to understand and respect sea life of all types, so in the sardine episode, why would they try to interfere when some sharks go after the sardines? (And yes, it's true that with it being a kids show, there's no way they could not save them once the sharks showed up, but why even write in that situation in the first place?)
  • They literally just saved Dina when Barnacles was leaving, so they couldn't let their rescue go to waste.
• How come the windows of the Gups or the Octonauts' air helmets can open and close while underwater with no visible water/air flowing in or out?
  • How do the helmets work at all? They seem to disappear into their collars when not being used, but form a seamless single piece when activated. What substance is flexible enough to do that? One fanfic theorised it was a nanomachine thing.
• How in the world did Barnacles survive being submerged in the whale shark's stomach acids?
• What the heck do they even eat? There are obligate carnivores like cats and a polar bear but all the animals they meet and save talk. What's more, even the vegetables are entirely sentient so not even the naturally vegetarian animals have obvious food sources.
  • Only the Vegimals are sentient, regular plants are not. They're seen eating the kelp cakes with smiley faces and the cakes don't express pain so presumably the faces are just drawn on.
• What are Peso's penguin species? He isn't Adelie, Emperor, Chinstrap, because they already showed in the series. Is he a Gentoo penguin, or a ficticious species? The other penguin species doesn't look like him.
• What even is the Octopod's propulsion system?