Why are vitamin `A` and vitamin `C` essential for us? Give their important sources.

Explanation

Vitamin A is essential for us because its deficiency cause xerophthalmia (hardening of cornea of eye) and night blindness.
Sources : Fish liver oil, carrots, butter milk, etc. Vitamin C is essential for us because its deficiency causes scurvy (bleeding of gums) and pyorrhea (loosening and bleeding of teeth). Sources: Citrous fruits, amla, green leafy vegetables etc.