In adult humans, _______ of lead or less in the blood is considered to be normal HomeCirculatory System MCQsIn adult humans, _______ of lead or less in the blood is considered to be normalQ. In adult humans, _______ of lead or less in the blood is considered to be normal.A. 40µg/dLB. 20µg/dLC. 10µg/dLD. 50µg/dLAnswer: 10µg/dL