Author Question: Stars are mostly made of A) hydrogen and helium B) pure hydrogen C) carbon, hydrogen, oxygen ... (Read 635 times)

neverstopbelieb · **on:** Jul 27, 2018

Stars are mostly made of

A) hydrogen and helium
B) pure hydrogen
C) carbon, hydrogen, oxygen and nitrogen
D) an equal mixture of all elements

Question 2

If Europa turns out to have a subsurface ocean which is a 100 km deep or more, how much water would this correspond to, compared to the amount of water in the Earth's oceans?

A) about the same
B) roughly twice as much
C) about ten times as much
D) roughly half as much