These bacteria used visible light energy to create chemical energy, expelling oxygen that was converted to ozone. The ozone blocked the Sun's harmful UV radiation from reaching the ground
Since the ancestors of modern day cyanobacteria added oxygen to the primitive reducing atmosphere of earth.
Explanation:
The primitive atmosphere of the earth did not have oxygen. So, life was not possible on land. The ancestors of modern-day cyanobacteria had the ability to carry out oxygenic photosynthesis which in turn releases oxygen as a by-product. Hence, these ancestors of modern-day cyanobacteria populated the land and added oxygen to the atmosphere of the earth.
Once enough oxygen was added to support the other life forms, aquatic life forms gradually started occupying the land habitats.
Estrogen is responsible for the reproductive system in women and high levels occur naturally during menstruation as compared to glucose levels in blood as the pancreas is constantly producing more insulin to lower the glucose in blood.
There is a scientific consensus that life exists on other planets
and
The scientists only studied one meteorite
The first one because the other ones don't make sense, and because it is a scientific consensus. The latter because they only studied one, and imagine if they studied other ones...
