Nerves connected to brain
message to the
heat sensors in the
spinal cord
skin of the hand
arm muscle
the effector
message from
the spinal cord
heat from the
flame
transverse section
through the
spinal cord
FIG 9.4.4 Reflex arc
Explain how the nervous system will respond in the above scenario.
[Use the RED ARROWS to assist in your response)

Which are reasons cells undergo cell division?

Which prefix mean under less or below

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?