Step 5: For the third list (Helium, Neon, Argon, Krypton, Xenon), recognize that these are noble gases and not biologically relevant elements in the human body. For the fourth list (Phosphorus, Sulfur, Magnesium, Lead, Mercury), note that Phosphorus, Sulfur, and Magnesium are among the ten most abundant, but Lead and Mercury are toxic heavy metals and not abundant in the human body.