Multiple choice

Which of the following elements is least present in the human body?

  1. Oxygen

  2. Hydrogen

  3. Iron

  4. Carbon
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the human body, the major elements by mass are oxygen (~65%), carbon (~18.5%), hydrogen (~9.5%), and nitrogen (~3.2%). Iron, while essential for hemoglobin and oxygen transport, is a trace element present in only about 0.006% of body mass. Among the given options (oxygen, hydrogen, carbon, iron), iron is present in the smallest quantity.

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