What allows reactions to take place to take place at a normal body temperature?
a enzymes add additional energy to chemical reactions.
b carbohydrates provide additional energy for body cells.
c lipids store extra energy that can be used in reactions.
d. enzymes reduce activation energy required for reactions.

You arrive late to a biological seminar. however, just as you enter the room, you hear the speaker referring to the "five-prime end" and the "three-prime end" of a macromolecule. immediately, you know that they are talking about a: ]

Solutions to environmental problems in europe must

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?