Science questions on Earth's HIstory?

Question

What are two events associated with the impact of a come or an asteroid with Earth that would cause a major extinction of life?

why did most of the iron that existed near Earth's surface around 4.5 billion years ago end up in Earth's core?

for the first question it's comet not come

aelius...the question says WOULD cause major extinction

Answer 1

1) We have only documented meteor impacts. But large enough asteroid or comet impacts could cause the same effect: massive seismic and volcanic activity which could blanket the sky with dust blocking out the sun.

2) One word: Differentiation. As the Earth cooled during its formation, lighter material like silicon and aluminum rose towards the surface to make the crustal minerals and rocks while heavier materials like iron sank towards to center forming the core.

Answer 2

For the second question, I think that the iron ended up in Earth's core because as Earth's temperature decreased after it was formed (before it had life on it) it began to cool down and it changed form which caused it to change to a different materail.

I don't know the answer to the first question.

Answer 3

A comet or an astroid did not cause a mass extinction of life, so that question is flawed.