Select all the correct answers.
A seismograph has a heavy weight that is hung from a spring. What would happen if the weight were attached to a rod instead of a spring?
The weight would not oscillate.
The weight would oscillate.
The pen would not make contact with the paper.
The seismogram would not be accurate.
The seismograph would not function.

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?