Which statement is most likely to be true, based on the drawings below? two skulls a. species a had more massive jaw muscles than species b. b. species a walked more upright than species b. c. species a was more capable of speech than species b. d. species a was more similar to modern humans than species b.

Development of new communities in disturbed environments, such as a burned or a clear cut forest, is called

Explain how the political influence of african americans leaders became weaker.

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?