11.     what are the two gases that escaped earth's atmosphere during early formation?  
            a.  hydrogen and helium    b.  helium and nitrogen    c.  hydrogen and nitrogen    d.  helium and oxygen 

A. Hydrogen and helium

Explanation:

Hydrogen and helium escaped the earth's early atmosphere. A cloud of gases surrounded the early earth that primarily had no magnetic field and gravity to trap some of the gases.

This was why these light weight gases were able to escape the early earth's atmosphere and we don't have them today.

i'm pretty sure it is letter c.) car