The cyanobacteria changed the composition of the earth’s atmosphere by evolving oxygen in what is referred to as the Great Oxygenation Event. This also allowed the ozone to be formed and block off most of the UV rays that are destructive to genetic material. Life was, therefore, also able to exist on land other than in water.
The red line is the wavelength
The blue line is the amplitude
Identifying the genetic sex of a child is based on finding intracellular Barr bodies that consist of inactive chromatin material.
Inactive chromatin material is the one where no transcription takes place. It is also known by the name heterochromatin. It appears as a dark condensed form in the chromatin.
Barr bodies are the inactive X chromosomes. These are mad inactive by a process termed as lyonization. It is essential to make the chromosome inactive in organisms with XY type of sex determination. They are present at the periphery of the nucleus. Inactivation of X chromosome makes the amount of X chromosomes equal in both, males and females.
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Answer: D volcanic eruption