Which best states the theory of plate tectonics?

a. earth’s continents were once joined together as one landmass.

b. earth’s layers consist of the crust, the mantle, the outer core, and the inner core.

c. earth’s surface is made of different sections of rock that move apart and collide.

d. earth’s most active volcanoes and earthquakes occur in the ring of fire.

Differentiate renewable and nonrenewable resources

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?

The polio virus can cause skeletal muscle paralysis by destroying neuron cell bodies. what area of the spinal cord is destroyed