(please hurry!!) Which name best describes the process of gas exchange?

A) Oxygen diffuses into the blood at the site of the heart, and carbon dioxide diffuses into the blood at the site of the alveoli.

B) Carbon dioxide diffuses into the blood at the site of the heart, and oxygen diffuses into the blood at the site of the tissues.

C) Oxygen diffuses into the blood at the site of the alveoli, and carbon dioxide diffuses into the blood at the site of the tissue.

D) Carbon dioxide diffuses into the blood at the site of the alveoli, ad oxygen diffuses into the blood at the site of the tissue.

Across of blue x blue (both heterozygous) would result in

Identify the structure in organisms that do not have kidneys that is adapted to regulate water balance

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?