The Earth was first considered habitable when we discovered that it was Microbial organisms that started the process. I would go with D.
Answer:
Oil spill
Explanation:
Its the oil spill because the pollution from it can be traced back to a specific source
Answer:
Water cycle is also called hydrological cycle. In this cycle water moved continuously above the surface of the earth for the continuity of life. Water is evaporated from the sea and ocean in the process of evaporation. This water goes to the atmosphere and form clouds. These clouds moves to hilly areas and comes to the ground in the form of rainfall and snowfall etc. Some water is stored on the mountains in the form of snow and the remaining downward through streams.
