What is the purpose of ethical guidelines for the handling of experimental subjecta?
A. To llat all of the materials that are needed to perform an
experiment on garden plante
B. To indicate that the research question under investigation has
never been asked before
C. To help scientista plan an experiment in which no animals or
humans are harmed
D. To make sure that the hypothesis is relevant to the research
question

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?