<span>The RNA world is the hypothesized format of chemical life that existed prior to our current DNA and RNA world. In the RNA world, RNA molecules formed in the primordial soup and began to evolve by self-replication and mutation. This led to increased complexity, natural selection of "better" RNA and diversification of RNA based life.</span>
Answer:
D. IV -> III -> II -> I
Explanation:
Blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. As the atrium contracts, blood flows from your right atrium into your right ventricle through the open tricuspid valve.
(C) earth's outer iron core
this is because iron is magnetic and therefore forms a strong magnetic field
