One difference between mixtures and pure substances is that
a)
mixtures can be physically separated.
b)
mixtures are made of one type of atom.
c)
pure substances have no chemical bonds.
d)
pure substances can be physically separated.

Apopulation has 1000 individuals. over a period of 1 year, 500 newindividuals are born. which equation shows how to calculate the birthrate ofthis population? a. 500 - 1000 = 0.5b. 1000 x 0.5 = 500c. 1000 - 500 = 2d. 1000 + 500 = 1500

In which squares should the phrase "green pods" appear a) a and d b) b and e c)a,c, and d d)a,b,c,d and e

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?