Which of the following sentences correctly describes the effect of an invasive species on an area? 1.Invasive species have naturally evolved to be top predators in an ecological area. 2.These species do not have a major effect on an ecosystem.
3 .However, they may decrease the population of local species.
4. This decrease causes a drop in local fishing yields.
5. Because of their exotic nature, invasive species boost local tourism.​

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?