not run away just becuase life seems hard does not mean you should run and just think how heart broken your mom and dad would be trust me I know i also thought that way once
The most common warning symptoms of a heart attack for both men and women are:
Chest pain or discomfort.
Upper body discomfort
Shortness of breath.
The oxygen in the upper atmosphere combine to form ozone layer (o3) that allows to colonize surface water.
Explanation:
The fossil stomatolites are formed at about 3.0 ga laminated bacteria. they form the sediments to fall into a thin film of bacteria, these bacteria binds with the sediment and grows through it.
Cynobacteria uses water, CO2 and sunlight to create their own food and produce oxygen as a by product. The significance of stromatolites is that they are earliest fossil evidence life on earth.
They were first organism to photosynthesis and produce oxygen.