Why doesn't the iPad need any RAM?

Hey guys,

I've looked at the iPad Air and though it's the current generation, it only seems to have 1gb of RAM.

Can anyone explain in layman's terms why iOS needs barely any RAM compared to Android and Windows 8?

I know it's the only operating system in the world that doesn't allow multi-tasking, but is that all there is to it?
Or does it just have so much faster SSDs that it can just read anything it just as fast as from the RAM?
Or are iOS Apps just much more space efficient?