useless trivia: What Word Means: A City In Denmark?

Questions

Arabian horses have one less vertebra in their backbones than other ----------?

Arctic terns found in North America and the Arctic migrate each year as far south as Antarctica and back, a round trip of over 18,000 miles. Theirs is probably the longest ----------?

A pig is a hog - but a hog is not a pig. "Hog" is a generic name for all swine. Per hog-raising terminology, a pig is a baby hog less than ----------?

A plaice, a large European flounder, can lie on a checkerboard and reproduce on its upper surface the same pattern of squares, for ----------?

A pregnant goldfish is called a ----------?