What is the most abundant compound in the human body?Group of answer choiceswateroxygenproteincarbon

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

What is the most abundant gases in the atmosphere?Group of answer choicesNitrogenCarbon dioxideHydrogenOxygen

Which of the following gases is the most abundant in the air we breathe?Group of answer choicesWater VaporArgonNitrogenOxygen

Which of the following elements is the most abundant in Earth's crust?Group of answer choicesCarbonIronOxygenSilicon

Which compound contains the greatest percent of oxygen by mass?Group of answer choicesSiO2 CO2SO2NO2