They all have 6 in its outer shell because they are all in the same group in the periodic table. Your VERY VERY welcome (:
The paternal (blue) chromosomal and the maternal (pink) chromosome are homologous chromosomes. Following chromosomal replication, the blue chromosome is composed of two identical sister chromatids and the pink chromosome is composed of two identical sister chromatids.
Homologous chromosomes bear the alleles for each character: homologous chromosomes have genes for the same characters located at the same positions along their lengths. However, two homologous chromosomes may bear either the same alleles or different ones. Alleles (alternative versions) of a gene reside at the same locus on homologous chromosomes dihybrid cross