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 are chromosomes that contain the same genes but each originate from a different parent. There are two instances in meosis where this occurs, Prophase I: Synapsis of homologous chromosomes allows of cross-over of genes between mother and father chromosomes. This mixing gives rise to genetic variation. Metaphase I-Anaphase I: Disproportiante division of parental chromosomes (aka disjunction) allows for further genetic variation. The separation of the homologous chromosomes is random. That is, a daugther cell can have most of its DNA comprised by mother chromosomes, or mosty by father chromosomes, or somewhere between these two extremes (The other cell will of course have the complemetary set).