(ii) Genotype ratio is 1:2:1, RR : Rr : rr Phenotype ratio is 3:1, round seeds : wrinkled seeds (iii) There are two sex chromosomes in human, X and Y. Females have XX chromosomes and males have XY chromosomes. (iv)  Mutation refers to the changes in the nucleotide sequence of DNA which can be inherited.  (v) The number of chromosomes in human beings are 23 pairs, that is 22 pairs of autosomes and one pair of sex chromosome. Thus, the gamete will have 23 chromosomes.