The ocean ecosystem has a high sustainability because of - A. the large variety of different organisms
B. green plants growing on the bottom
C. predator/prey relationships

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.