Final answer:
Iron deficiency anemia is the most commonly seen deficiency symptom of inadequate iron intake. It can cause weakness, fatigue, poor concentration, shortness of breath during activity, and increased mortality in infancy.
Step-by-step explanation:
The most commonly seen deficiency symptom of inadequate iron intake is iron deficiency anemia. This occurs when the body does not receive enough iron to produce sufficient hemoglobin, which is needed to bind oxygen and carry it throughout the body. Symptoms of iron deficiency anemia may include weakness, fatigue, poor concentration, shortness of breath during activity, and increased mortality in infancy.