By weight, about 65 percent of the human body is which element?

Norse settlers began arriving around 874 on which North Atlantic island, which founded its Althing parliament in 930? Dutch elm disease devastated which North American tree, once a favorite for lining city streets? While living in the U.S., which scientist was offered the presidency of Israel in 1952? By tradition, no pope ever chooses which name? Which nomadic desert people of the Middle East are famed for breeding Arabian horses? Explorer Richard Byrd's polar career began with an expedition based at Etah, on which large Danish-ruled island? Which British naval hero helped win the Battle of Cape St. Vincent in 1797? Byron was Lord Byron from age 10, but which poet had to wait until his 70s, in 1884, to become a lord?