Read the given passage and answer the question that follows.

There are three main groups of oils: animal, vegetable, and mineral. Great quantities of
animal oil come from whales, creatures of the sea, which are the largest of the remaining
animals in the world. To protect the whales from the cold of the Arctic seas, nature has
provided them with a thick covering of fat, called blubber. When the whale is killed, the
blubber is stripped off and boiled down. It produces a great quantity of oil which can be made
into food for human consumption. A few other creatures yield oil, but none so much as the
whale. The livers of cod and halibut, two kinds of fish, yield nourishing oil. Both cod liver oil
and halibut oil are given to sick children who need certain vitamins. No household can get by
without oil, for it is used in cooking. Perfumes and soaps may be made from the oils of certain
flowers.