Which of the following statements about the uterus is not correct? the uterus is anterior to the urinary bladder. the fundus is the portion of the uterus that is superior to the uterine tubes. the isthmus is located between the body of the uterus and the cervix. the internal os is the superior opening of the cervical canal. the cervix projects inferiorly and posteriorly.

Astudy by solloch and et. al., in 2017, gives the map above which shows the frequency of alleles with a ccr5-delta32 mutations over 87 different countries. this mutation deletes the presence of a co-receptor (ccr5) on the outside of human t-cells (lymphocytes). some viruses, such as the one responsible for the black death and human immunodeficiency virus (hiv), require this receptor for attachment to host cells during the infection process. the black death was an epidemic that passed over northern europe during the 14th century killing nearly 60% of europeans. according to this information, which explanation best explains why northern europeans show a greater immunity for hiv than some other parts of the world?