Explain how the concept of the “survival of the fittest” relates to the theory of evolution.

The fittest species for a certain biome will adapt and change so as to keep living. This process is evolution and an example can be giraffes. If they had smaller necks, they couldn't reach the tree tops where food is, so only the fittest one with large necks survived, and they evolved by having the entire species grow up with large necks.

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.