What are some examples of negative feedback? Select all that apply.

The body produces a protein. In turn, the protein triggers the body to make more of the protein.
Pupils getting smaller to reduce the amount of light reaching the eye when the light is very bright.
Cells increasing their activity to produce more heat when it is cold.
The kidneys reducing the water level in the body when a person drinks a lot of fluids.

WILL GIVE BRAINLIEST

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?