Answer:
Krishna is probably suffering from vitamin A deficiency.
Explanation:
Vitamins are considered micronutrients as the body only needs small amounts of them to function perfectly.
Vitamin A is an indispensable element for ensuring not only visual acuity, but proper growth and tissue differentiation. Lack of this vitamin can cause blindness, poor night vision, xerophthalmia, also called dry eye or keratoconjunctivitis sicca, a disorder that is not only characterized by changes in tear production or composition, but also produces dryness of the skin, cornea, conjunctivae and the appearance of small white spots in the sclera (Bitot patches). In the most severe cases of xerophthalmia, corneal ulceration and necrosis may occur.
According to the symptoms that Krishina and her parents have, we can say that she is likely to be vitamin A deficient.