In the past, earths sea level has sometimes been lower. at that time, which of the following would have been a major difference in the ocean basins?

Florian discovers a rock that is broken into pieces. each piece has several bands. which type of rock does florian predict these pieces will change into when subjected to heat and pressure? igneous magma metamorphic sedimentary

Which is the best example of plant tissue? the answer is d (just took the test)

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?