Answer: C. Pylorus
Explanation: In order to prevent the backflow, Pylorus is divided into two parts, the tantrum that connects it to the body to the stomach.
Chromosomes are structures of nucleic acids and protein carrying genetic information in the form of genes.
The chromosome is composed of two sister-chromatids.
During meiosis and mitosis, the sister chromatids are separated to separate half of the geentic material and create a new cell.
The difference between sister chromatids and non-sister chromatids is that sister chromatids have the same alleles in the same place and non-sister chromatids have different alleles in the same place. Non-sister chromatids will have the same length and configuration, but those different alleles will represent different types of the same characteristic (for example: different colors of fur). But they look the same as sister chromatids.