The most abundant element (by mass) in the human body is :Group of answer choicesPotassium (K)Nitrogen (N)Oxygen (O)Carbon (C)

To determine the most abundant element by mass in the human body from the given choices, we can consider the general composition of the human body.

1. Analysis of Elements:

   • The human body is primarily made up of water (H₂O), which contains hydrogen and oxygen.
   • Major elements also include carbon, nitrogen, hydrogen, and oxygen, with oxygen being a significant part of bodily mass.

2. Relative Mass Contributions:

   • Oxygen (O) accounts for about 65% of the body's mass.
   • Carbon (C) makes up about 18%.
   • Hydrogen (H) is around 10%.
   • Nitrogen (N) is approximately 3%.

3. Conclusion:

   • Among the options given, Oxygen (O) is the most abundant element by mass in the human body.

Final Answer

Oxygen (O) is the most abundant element (by mass) in the human body.