Flud

Then why do your parts change their skin so often, if not to protect themselves from the light that surrounds them?

Explain change skin.

  Your parts have additional skins that they crawl out of when they enter the atmosphere, and into again when they leave. What are the skins for?

Protection bright animal.

Ah, it damages your parts also?

Yes. But atmosphere damage skins.

  Thus, crawling out of them. Is that also why your parts wear shells?

Explain shells.

  The shells that rest on the boundary layer. Your parts wear the skins to protect from the bright animal, and the shells to protect their skins from the atmosphere. Is this correct?

Shells protect life from atmosphere.

  Protect the parts' lives, not just their skins?

Correct.

  ...But your parts go into the atmosphere voluntarily. Why would they, if it's so dangerous?

Atmosphere normal, safe. Atmosphere increase, danger.

  If we understand this, it isn't the atmosphere itself but the amount of it that harms the parts. Does this increase happen often?

Twelve bright animal sleep cycle.

  This is a new idea to us, the atmosphere rising and falling. What was the sound you made? "Flud"... And you live with it constantly?

Small flud, often. Small shells. Big flud, rare. Big structure shells.

  You are talking about those structures your parts rest in? They are also boundary shells?

No flud, big structure stand. Big flud, big structure shell.

  We understand this now. A big structure of the right shape can be a boundary shell when the atmosphere increases too much for the smaller shells. But since an increase like that is uncommon, those structures stand on their own most of the time.

Correct.

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  Big structures... We don't need such a thing, but it might be good to have something to shelter our collections from atmosphere falling from the upper part of the world.