What is the fundamental reason that Mars, unlike Earth, has ...

[savannahhooper]

What is the fundamental reason that Mars, unlike Earth, has become virtually geologically dead?
 
  A) its small size compared to Earth
  B) its large size compared to Earth
  C) its farther distance than Earth to the Sun
  D) its closer distance than Earth to the Sun
  E) its rapid rotation compared to Earth
  F) its slow rotation compared to Earth

Question 2

Process of Science: Why is it important to understand the Sun in order to understand the Earth's radiation belts and space weather?
 
  What will be an ideal response?

[juicepod]

Answer to Question 1

A

Answer to Question 2

Solar activity causes the responses in the near-Earth space environment that produce changes in the radiation belts, so an understanding of how the Sun changes is directly relevant to space weather.

[savannahhooper]

Excellent

[peter]

Thanks for the timely response, appreciate it