The Precambrian time refers to the time 4.5 billion to 542 millions year ago. This period is characterized by having reduced atmosphere and included reduced compounds. Scientists believed that atmosphere at that time was devoid of free oxygen and CO2 was present in excess. Before the complex life evolved on the Earth, the Precambrian Earth's ocean contained dissolved carbon dioxide.
The answer is B because when hydrogen is separated from O2 it soluble
Plant cells have a cell wall and cell membrane but animal cell have only a cell membrane.
Answer:
ok and what about them ??????????
