Explanation:
1. abnormal conditions due to the absence of specific substances usually found in a normal diet
Deficiency disease
2. susceptible to infection, partial or complete blindness, unhealthy skin
Vitamin A deficiency
3. fatigue, depression, irritability, low blood pressure, loss of appetite
Vitamin D deficiency
4. inflammation of the mouth, sores around the mouth, red and thickened skin, diarrhea, vomiting, etc.
Niacin (B3) deficiency
5. weakness, bleeding into tissues, excessive bruising, softening of bones
Vitamin C deficiency
6. bones not normally hardened and become bent or twisted
Vitamin B1 deficiency
