1) Moving water takes more muscle power than moving air
2) Mammals (such as us) are warm blooded so our oxygen requirements are high. Fish and other gilled creatures are cold blooded and thus can actually survive on the amount of oxygen dissolved in water. We cannot.
Apparently you didn't get the joke.
Of course if running DOS games at their appropriate speed is your goal, then DOSBox is obviously the solution...
Physically, teenagers are adults (biologically able to procreate)...
Sure, physically teenagers are adults, but there's abundant evidence that the frontal cortex is not fully wired until your mid-twenties.
This means that teenagers have empirically measurable cognitive deficits in things like: organizational thinking, executive functioning, empathy, attentional control, judgment of consequences... and a whole host of other mental capacities associated with adult frontal lobe functioning and decision making.
So, no, the laws aren't arbitrary. Sure, maybe the people making them didn't have this research at the time - but they were definitely intuitively aware that teenagers as a group did not display the same kind of mature and responsible thinking as actual adults.
All great discoveries are made by mistake. -- Young