Read this: The chemical composition of wood varies from species to species, but is approximately 50% carbon, 42% oxygen, 6% hydrogen, 1% nitrogen, and 1% other elements (mainly calcium, potassium, sodium, magnesium, iron, and manganese) by weight. Wood also contains sulfur, chlorine, silicon, phosphorus, and other elements in small quantity.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): What element joins potassium, calcium, manganese, iron, and sodium to make a combined 1% of the chemical composition of wood?
magnesium