Question 3 The diagram below represents a stack of rock layers. Examine the diagram, and answer the question that
follows.
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4
3
2
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What do these layers and their fossils suggest about Earth's history?
A. There have been changes in Earth's lifeforms over time.
B.
Only one kind of lifeform lived where these layers formed.
c. Lifeforms on Earth have been the same over time.
D. No lifeforms were present when these layers formed.
Question 4

Sweating and breathing is an example of differentiation specialization maintaining homeostasis metabolism

Explain the source of radioactivity in uranium in earth’s crust by which it produces nuclear radiation

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?