Insufficient intake of iron will first affect the body's levels.

Had to look for the options and the answer that fits the blank is HEMOGLOBIN. Upon assessment of one's blood, when one's hemoglobin is lower than normal, this would mean that iron is insufficient in the body and therefore, the person is encouraged to take some supplements. Hemoglobin is very important in the normal functioning of the body as this brings oxygen all throughout the system.

Answermaintaining a balance of physical, mental, emotional,and social well being;