No.
The rocks are constantly expose a geodynamic processes that after thousands or years finally result in the formation of others rock with different characteristics.
The processes that affect a rock depend in the kind of rock and the place in the earth structure it is located.
But rock in the earth surface are expose to weathering that can be produce by physical or chemical factors. The final result of the weathering is the fragmentation of the rock in particles and transportation of these particles by wind or water to a different place.
In this different place the particles will participated in the formation of new rocks.
This is the simple explanation of formation cycle of sedimentary rocks.
Of course they can. The overall compositions of the rocks will remain the same (assuming a closed system, which isn't always the case), but mineralogically there will be changes due to metamorphic pressures and temperatures. There are a whole list of minerals which only formed from metamorphic processes.
Nothing. They always remain the same.
yes.
Mitochondrial DNA will remain the same for generations and they are inherited from the mother.
It doesn't ... its always changing.
It doesn't ... its always changing.
Mostly with some exceptions .
The ocean's salinity remains the same because of all of the salt spray. It is always spitting out salt from the ocean. Also the sea life uses the salt in various ways. Another reason is that rocks take salt from the ocean as they form over time.
some rocks stay the same but some break into little bits
no. your social security number will always remain the same.
no, if that were true we would all still be a single cell
yes (unless deliberately physically altered)