Author Question: Of all the chemical elements, the one most crucial to the complexity of life is: A) hydrogen. B) ... (Read 31 times)

debasdf · **on:** Jul 27, 2018

Of all the chemical elements, the one most crucial to the complexity of life is:

A) hydrogen.
B) oxygen.
C) sulfur.
D) carbon.
E) nitrogen.

Question 2

What is unusual about the motion of Phobos, as seen from the surface of Mars?

What will be an ideal response?

nekcihc358 · **Reply #1 on:** Jul 27, 2018

Answer to Question 1

D

Answer to Question 2

While its orbit is equatorial and counterclockwise, it takes less time for this very close satellite to orbit Mars than for Mars to rotate. From the surface, Phobos would overtake the observer, rising in the west and setting in the east several hours later.