5. The Gakkel Ridge is an area where two ocean tectonic plates are diverging. What can you conclude is happening in this area?
A. The plates are moving away from each other and creating a mid-ocean ridge
B. Frequent earthquakes are caused by the plates moving towards each other
C. One plate is being slowly subducted underneath the other plate, creating
volcanoes
D. Deep trenches and crevices are formed when the plate boundaries rub past
each other

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?