Until the early Proterozic there were only negligible amounts of free oxygen in the atmosphere
<span>it is the study of human activities on the surface of the globe
(regions inhabited <span>by men)</span></span>
The answer is "Delta"
Delta is a flat triangular shaped land formed when a river carries and deposits
sediment at its mouth.
This usually happens where a river is entering an ocean, sea,
lake, reservoir,
and another river that cannot carry away the sediment supplied by the river.
The last one happens very rarely (Entering a river).
