The answer is
<span>E. There is at least one steep slope and one gentle slope.</span>
Water is the source of life. It is one of the only ways to survive so without water, there is no life.
The concept of Peak Oil was first developed in the 1950's by the geologist M. King Hubert.
The fact that volcanic rock has often been found early in the rock record but less frequently in later rock layers suggest to scientists the following conclusion about early earth: <span>volcanic activity was more common in the past than it is today.
</span>Besides volcanic activity in general, also huge volcanic eruptions<span> were much </span>more common than today<span>.</span>
