The correct answer is A.primary, because a primary landform is a natural feature on earth's surface.
A seems most probable.
Oceans are also deeper and larger then Seas.
Fish live completely in water, amphibians partly in water and land while reptiles live on land. Fish and reptiles have scales while amphibians have smooth skin. Fish breath through gills, amphibians through gills and lungs while reptiles through lungs. They are generally classified as vertebrates.
Explanation: this experiment is long term which means patience is compulsory. you need to have a wild sloth and a domesticated sloth adopted right at their birth (he should be in a controlled environment that mimics the wild). your domesticated sloth shouldn't have the algae. at their middle age, you should compare them with them from every aspect.