I'll mark brainliest, please, I need it! The following diagram shows the branching tree for four kingdoms and some of their shared derived characteristics.

A slanting line is shown. There are four lines drawn vertically on this line at equal intervals. There is a black circle between each pair of these vertical lines. Protists, Plants, Fungi, Animals are written on top of each vertical line in order from left to right. Common Cell is written on the left most end of the sloping line. The second black circle has Mostly Multicellular written on it. The first black circle has X written on it.

What shared characteristic can be written at point X? Use complete sentences to explain your answer.

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?