Unit test Based on the data, which of the following statements best describes an effect of population density on rat
populations?
Choose 1 answers
High population density decreases the birthrate,
B
High population density increases the number of successful matings.
High population density increases the male to female ratio.
High population density decreases the death rate.
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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?

The source of energy shown in the image is (renewable, non renewable, polluting) a drawback of building a dam is that (it will destroy ecosystems, it requires fossil fuels, it won’t be useful for irrigation)

Australopithecus robustus was likely the longest-surviving species of australopithecine in south africa. it had: a. large molars, a big face, and a sagittal crest. b. a large body, large teeth, and a sagittal crest. c. a big brain, big teeth, and a big face. d. a big face, large teeth, and a large body