each range is identified with a range reference that includes the cell reference of the upper-left cell of the rectangular block and the cell reference of the lower-right cell separated by a .

Consider the last statement in the prompt: "people take such environmental factors into account in their choices when deciding where to live." do all people have a choice as to where they live? what factor plays a key role in this decision and may therefore play a large role in determining quality of life?

_tissues respond quickly to outside stimuli a) epithelia b)nervous c)muscular d)muscular and nervous

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?