How are catastrophic events related to changes in geological timelines?
a. they aren't related to changes in the geological timeline because they don't change the overall population dynamics.
b. they define geological periods because scientists use them as reference points for tracking the history of the earth.
c. they aren't related to changes in the geological timeline because the timeline is dictated by temperature cycles.
d. they cause significant changes that disrupt the equilibrium of the earth and lead to natural separation points.

The correct answer is D) They cause significant changes that disrupt the equilibrium of the earth and lead to natural separation points.

The catastrophic events related to changes in geological timelines cause significant changes that disrupt the equilibrium of the earth and lead to natural separation points.

Historians and scientists use catastrophic events because they mark the end of an era and the beginning of a new epoch in the history of humanity. Earthquakes and floods, even meteorites, have changed the face of the Earth and its inhabitants, in most of the case the animal life on the planet. We are referring to the extinction of the dinosaurs, or glaciers melt that covered many sites, and other kinds of catastrophes that science used them as a natural separation point.  

sorry its a lil late, but the answer is d. the rotation 180° about z'

the united states broke it's neutrality was the constant german sinking of trading vessels resulting in the loss of lives, one example would be the lusitania.