What band worn around the upper arm is often a sign of mourning?

Under a 1949 treaty, which much larger neighbor agreed to guide Bhutan's foreign affairs? What word names both the biblical vessel that held Noah's animals and the chest that held the Ten Commandments? Which biblical figure owned a donkey that spoke to him? Bishop James Ussher, a 17th-century Trinity College Dublin scholar, dated which event to October 23, 4004 BC? "Bicycle Race" and "Another One Bites the Dust" are hits by which rock band? Bicycle shorts often contain which spandex fiber, a DuPont trademark introduced in 1958? "Bicycle Wheel", "Fountain" and "Nude Descending a Staircase" are works by which artist? Which auction house held its first sale in London in 1744?