During the early earth, when photosynthesis has not yet evolved, there were only negligible amounts of free oxygen in the atmosphere. It was said that the Earth's atmosphere had no free oxygen then. This is about 3.5 billion years ago.
Answer:
human factors:
Access to a freshwater supply is affected by the following factors: Climate – low levels of rainfall and high temperatures lead to water deficits . When rainfall is low, there is less water available. When temperatures are high, water evaporates and so there is less available to use.
environmental factors:
Sedimentation.
Runoff.
Erosion.
Dissolved oxygen.
pH.
Temperature.
Decayed organic materials.
Pesticides.
Explanation:
no explanation. already explained in the answer
C. Law of superposition because it is the principle that the oldest layer of sediment will be found on the bottom
The three regions are Melanesia, Micronesia, and Polynesia.