Almost everything is powered by AC. The things that actually work on DC like electronics, have power adapters to convert AC into DC for the device, like the little brick that comes with your laptop or phone charger.
There are rare exceptions, but EILI5 doesn't care about those.
Yes, but to OP's point, it does get more detailed. How do you define uptime? I've seen contracts where uptime is not well defined, and I've seen other that are very prescriptive and some in between. E.g. All users access attempts must be responded to in under x many seconds and even milliseconds, 99.5% of the time. Other say peak loads over x many users, must have access on the 3rd try after getting a "site is busy, please try again" message. It all depends on what the site is and what they do because going to 99.99% for all users gets expensive.
A lot of web apps today are intermingled with loads of bloat from 3rd party sass providers that slow things down and increase transmission loads and failure at any one of them can cause a site to slow down to trigger a "downtime" quota even if the site works and the users successfully did their thing. (Because the sass failure was not critical).
You make a great point. Obnoxious clarification - Ethanol evaporates about 5x faster than water. The exact details depend on the % of ethanol to water, and the distillation type.
Distillation will force most of the alcohol off first as only some of it is bound to the water, depending on the method and concentration before an azeotrope is found. The azeotrope is where the water and alcohol are bound and can't be further separated by distilling and boil off together. It's around 95% ethanol 5% water.
Few think, about anything. It's mostly victims of a cohesive ragebaiting program. Russians successfully did it to the American right. Now both are doing it to the Canadian right.
I suffer for my art.