What geological evidence could there be for the presence of an early ocean? Select one:

a.
Marine sedimentary rocks can be dated back about 4 billion years.

b.
The iron contained in the rocks combined with the oxygen to form reddish iron oxides.

c.
Oxygen is needed to make ozone, a molecule made of three oxygen ions, O3.

d.
No animals would have been able to breathe in Earth's early atmosphere.

Aflashlight produces light using energy from the batteries. in which order does the energy change form? a. from chemical to electric to light energy b. from electric to light to chemical energy c. from electric to chemical to light energy d. from light to electric to chemical energy

Explain how you will prioritize tasks in the medical office by immediate, essential, or optional. how will you re-prioritize when disruptions occur?

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?