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.
We know that homologous chromosomes have to pair up during meiosis, but exactly how they do this remains a bit of a mystery. One of the tricky things about studying homologous chromosomes is that different species use different mechanisms for pairing their chromosomes.