my daughter 2 years and 2 month old, she often biting her nails.please suggest me if she is lack of any deficiency.

A. It is not because if some deficiency. It starts as a self soothing behaviour like due to anxiety, stress or fear like that. Then it becomes a habit and sometimes an addictive habit. You can encourage her through some rewards like giving a sticker for every one hour she stays away from biting nails. Then after she collects ten or twenty stickers give her a gift.