Deficiency Diseases and Disorders

Meat, eggs, and milk are rich in protein and B vitamins, but they contain little to no Vitamin C. A diet consisting only of these foods will eventually lead to scurvy.

Keratomalacia is a severe eye condition resulting from advanced Vitamin A deficiency, where the cornea becomes soft and opaque.

Rickets: This condition is due to a lack of vitamin D, which causes the body to be unable to absorb or deposit calcium.

Hence, Option D is correct.

Hypochromic (pale) and microcytic (small) anemia is typically caused by iron deficiency. Macrocytic anemia is usually caused by Vitamin B12 or folate deficiency. Given the options, iron deficiency is the most common cause of hypochromic anemia.

Pernicious anaemia marked by a decrease in the number of red blood cells which is caused by a reduced ability to absorb vitamin $B _{12}$.

Anaemia is most commonly caused by a deficiency of iron (Fe), which is essential for the production of hemoglobin in red blood cells. While other minerals are important for health, iron deficiency is the primary nutritional cause of anaemia.

Goitre is an enlargement of the thyroid gland, which is most commonly caused by a deficiency of iodine in the diet. Iodine is a critical component required for the synthesis of thyroid hormones.

Goitre is primarily caused by iodine deficiency, which is a mineral, not a vitamin. Keratomalacia and xerophthalmia are caused by vitamin A deficiency, and Addison's disease can be associated with various causes, but goitre is the classic example of a mineral-deficiency disease in this list.

Iron is an important requirement for the biosynthesis of hemoglobin in human body. Hence, iron deficiency will lead to deficiency of hemoglobin, i.e., reduction in oxygen carrying capacity of blood called as anemia. Hypochromic anemia is a generic term for any type of anemia in which the red blood cells (erythrocytes) are paler than normal. It is important to note that iron is not readily absorbed in the body. Vitamin C enhances iron absorption in body. Hence, iron rich food like non vegetarian diet is usually served with salad sprinkled with lemon juice.

Leukopenia, or a decrease in white blood cells, is often associated with deficiencies in folate or vitamin B12. While the question lists Cyanacobalamine (B12) as correct, it is a common medical fact that both B12 and Folic acid deficiencies cause this condition, making the question slightly ambiguous.

Anemia occurs when a person has lower-than-normal levels of red blood cells (RBCs) in the blood. Iron-deficiency anemia is the most common type of anemia, which occurs when your body does not have enough of the mineral iron. Your body needs iron to produce a protein called haemoglobin, which is responsible for carrying oxygen to your body’s tissues. Your tissues and muscles need oxygen to function effectively.

Kwashiorkor manifests symptoms of protein deficiency. This can be prevented by giving children protein rich diet.

When people do not get to eat a balanced diet and hence miss out on the recommended daily quota of carbohydrates, fats, vitamins, minerals, iron, calcium etc. the condition is called malnutrition. Diet taken by people does not contain sufficient nutrients in such case.