Is it ensure, insure, or assure?
any of the group of seabirds that includes the albatrosses (family Diomedeidae); shearwaters, fulmars, prions, and large petrels (Procellariidae); storm petrels (Hydrobatidae); and diving petrels (Pelecanoididae). There are approximately 117 living species of diverse sizes and ranges. All Procellariiformes are recognizable by their conspicuous tubular nostrils, which project upon the culmen (upper bill). This feature gives the order its alternative name, Tubinares, meaning "tube-nosed." The feet of the birds are webbed, and the hind toe is either vestigial or missing. All species have a characteristic powerful musky odour, which is caused by the excretion of stomach oil. The oil can be used as a defensive discharge through the mouth when the bird becomes alarmed.