Which of these statements describes iron
A)It can combine reversibly with O₂.
B)Deficiency can lead to polycythaemia.
C)It is converted into bilirubin and secreted into the bile when old red blood cells rupture and are degraded.
D)It appears reddish when combined with CO₂.

Question

Quizplus · Accepted Answer

Iron can combine reversibly with oxygen to form oxyhemoglobin in red blood cells.

Answer: D 
 Iron appears reddish when combined with carbon dioxide in a compound called iron carbonyl.

B and C are incorrect statements. Iron deficiency can lead to anemia, not polycythemia, and bilirubin is not a product of iron breakdown, but rather of heme breakdown.

Which of These Statements Describes Iron