So, here’s the problem. I was discussing today with a few friends, if there was an aquatic life form, like a fish or an octopus. Could that life form theoritically develop into one that can leave their home planet.

These are the conditions:

1. This species is highly intelligent (at least as much as humans have become).
2. This species can only survive in water and breath in water, like most fish and unlike frogs which can breathe in both air and water.
3. This species cannot evolve into one that can breathe air either.

The problem that I foresee with this species developing into a space fairing one is that it would be impossible to create fire underwater and I think we can all agree that fire might be mankind’s greatest discovery. So how would this species overcome this hurdle, I get that underwater volcanoes are a thing but I don’t think it is possible to harness them well enough to weld and make whatever versions of transportation and building this species would make.

So could they make it out of the atmosphere of their home planet? And how far after that?

Why do we take height of real and inverted image fromed by convex lens as positive

Hi all, not sure if this is the right place for this, but I'm looking for a paper I remember reading a while back. The gist of the paper was that children picked their own diets and ended up picking a healthy diet with all the required nutrients. Even children who were deficient in absorbing a specific nutrient (e.g. iron) ate enough to satisfy that deficiency.

Is anyone able to help me out and find it? I've tried searching google scholar but haven't had any success yet.

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Edit - found it: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1626509/