Deficiency of which vitamin causes night-blindness?

i) Night blindness is caused due to the deficiency of vitamin A.
ii) Uracil is the base that is found only in the nucleotide of RNA.
iii) The reaction of glucose with HI giving n-hexane suggests that all the six carbon atoms are linked in a straight chain, as shown in the reaction given below:
CHO−(CHOH)4−CH2OH + HI →Δ CH3−CH2−CH2−CH2−CH2−CH3