Question 1
Earth's original atmosphere, several billion years ago, was ________ the present atmosphere.
◦ somewhat similar to although containing more oxygen than
◦ completely unknown and thus cannot be compared to
◦ much different from
◦ exactly the same as similar to
Question 2
The salinity of the oceans is ________.
◦ staying the same
◦ continually decreasing
◦ fluctuating
◦ continually increasing