Question

the human body is made up of mostly: carbon dioxide. oxygen. hydrogen. sodium.

Explanation:

The human body's elemental composition: Oxygen is the most abundant element (by mass) in the human body, making up a large portion (around 65%). Carbon dioxide is a gas we exhale, not a major component of body structure. Hydrogen is present but not the most abundant. Sodium is a minor ion. So the correct option is the one with oxygen.

Answer:

The correct option is the one labeled with "oxygen" (the second radio button option in the list: "oxygen").