Answer:
The correct answer is "#2 and #3 only"
Explanation:
A and a are alleles, and R and r are alleles. Alleles of a gene are found at the same locus on homologous chromosomes. Every pair of the alleles depicts the genotype of a particular gene. Homozygous genotype occurs when two similar alleles at same locus and heterozygous in case of two nonidentical alleles. Due to the alleles there occurs a change in the appearance. An alleles create differences in gene.
