That's Roman numeral 40, of course, not "extra large". What a lot of questions !
1) How can you get nothing out of nothing, before the Big Bang ?
This is literally as good an answer as anyone else will tell you, 'cept they'll make it sound more sciencey.
2) Is gravity a constant or does it change with the size of each object ?
Gravity is determined entirely by the mass of your mum.
3) Why is the Moon leaving Earth ?
That too relates to your mum. Best not to ask.
4) If spatial topology reveals itself to be constitutively hyper-toroidal, are doughnuts a good source of nutrition ?
5) How come gravity is stronger on smaller objects ?
It just is.
6) How come we're not squished into puddles of goo because of gravity ?
That sounds like a challenge to me !
7) Does the Moon have a real name ?
Yes, it's Mickey. Mickey the Moon.
8) What do you think of this video about NASA being speechless about the discovery of a super-powerful object billions of light years away ?
It's quite silly.
9) Is it important to clean the Arecibo telescope every time a bird poops on it ?
Oh yes. That's what graduate students spend most of their time doing, when they're not making tea, of course.