Collapsing is the correct spelling, yes.
Some example sentences are:
The shelf ended up collapsing an hour later.
You need to stop collapsing on me.
They worked hard to stop the tower from collapsing.
collapsing=falling apart
The word is spelled "collapsing" (falling down).
Yes. Santorini is a stratovolcano, or at least it was before collapsing into a caldera.
Collapsing in Europe
yes you spell it like this
Collapsing Opposites was created in 2002.
Yes, that is how you spell occupied.
Yes, that is how you spell whiskers.
Collapsing in Europe
Yes, "seems" is the correct way to spell it.
Yes
don't know by keeping the structure good collapsing