What process that brings heat from the lower mantle toward the crust?

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.

The fraction of an original sample of tritium that remains unchanged after 24.62 years is 1/4. if you need the percentage it is 25%

Answervolume