This week, you learned about deforestation. this process clears out trees and plants
to create new farmland and pastures. however, unbalanced deforestation (cutting
down forest without planting new trees somewhere else) has also turned some areas
into deserts and increased climate change and carbon dioxide emissions.
based on this information and what you learned this week about plants,
transpiration, and photosynthesis answer this question:
why do you think that planting new trees and plants is an important part of fighting
against deforestation's effects?

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?