It means your egg is starting to hatch!
If you mean the friend area called Dragon Cave, these are the Pokemon that will live there when recruited: Bagon, Shelgon, and Salamence.
If you mean the deep hole in the middle of the cave at the North Pole in the first level, that gap doesn't do anything. You can only walk around it. You cannot intentionally walk into it.
It means to use flash in the middle of the cave
You go to Bloomingdale then north from there. Or do you mean how you get to the Bad Cave (deeper into it)?
you mean dragons den? you have to defeat Clair the gym leader first.
A dragon needs to be in a well lit, warm environment with proper lighting and attention. They need full daytime access to UVB lighting or they will die. I am not sure what you mean by a hole, but Im going to go with a solid NO.
If you mean as a pet, there is armored frost dragon which is now rare but was dropped from the frost dragon on mount frost or the armored baby frost dragon which is also now rare but was the reward from the quest Turn Dracolich into Dragon. If you mean how to get to it, then that too is rare but was located in Ice cave (/join icecave) or Mount Frost (/join mountfrost).
Drache is literally interpreted as "Dragon." Originally spelled "Trache" from middle high German.
If you mean the door on the east side of the first area, it must be opened from the north side.
If you mean "our galaxy", yes. There is a black hole with a mass estimated at 4-5 million solar masses in the center of the Milky Way.
Oh, you must mean the dotted hole on six island. Right? Well if you are talking about that, dotted hole is not talking in brail. It is talking in regi. Regirock, regice and registeel spoke this long ago, and you must go deep inside the cave to retreive the sapphire that leads to mewtwo.
The biopsied piece shows a hole in the skin in the middle and pus and plasma over the top of the hole.