Theres no environment I can think of that would have remained constant enough to preserve dinosaur DNA.

Nuclear DNA encodes all the proteins and enzymes that make you you, basically.

I laughed when Steven Spielberg said that cloning extinct animals was inevitable. But I'm not laughing anymore, at least about mammoths. This is going to happen. It's just a matter of working out the details.

Theres no environment I can think of that would have remained constant enough to preserve dinosaur DNA.

There is no good scientific reason to bring back an extinct species. Why would one bring them back? To put them in a theme park?

The study of evolution is an evolution in itself.