"The gazelle is the most graceful./The rhinoceros is the least graceful."
"Which one is the most/least colorful?"
"The bird is the most colorful./The polar bear is the least colorful."
"Which one is the most/least expensive?"
"The computer is the most expensive./The calculator is the least expensive."
"Which one is the most/least delicious?"
"The steak is the most delicious./The parfait is the least delicious."