I think B seems like the answer.
Answer:
difference in density
Explanation:
We know that the high central density suggests the earth must be rich in nickel and iron and that much of the core must be liquid. This lower-density air then rises and is replaced by cooler, higher-density air. The result is atmospheric circulation that drives the weather and climate through redistribution of thermal energy.
Most important are the many striking similarities between prokaryotes (like bacteria) and mitochondria: Membranes — Mitochondria have their own cell membranes, just like a prokaryotic cell does. DNA — Each mitochondrion has its own circular DNA genome, like a bacteria's genome, but much smaller.
Fertilization --> Embryo --> Fetus
Thru 8 weeks
