DNA is the molecule that carries genetic information of a given organisms. Genetic variation is the changes that occur in the genome of an organisms to help an organism adapt well to the environment, however, they might also be disadvantageous. The variation in DNA sequences are useful in building a tree of life because DNA sequences are similar in closely related organisms and less similar in less closely related organisms.
Answer:
theoder schwann and Rudolph Virchow
In DNA methylation, the most frequently methylated nitrogenous base is the cytosine. Its methylation is widespread in prokaryotes and eukaryotes. Its rate of DNA methylation differs greatly between different species like Arabidopsis thaliana which is 8%, Physarum, 4%, Mus musculus, 2.3%, and etc.
I am not sure but I am guessing carbon and nitrogen :)
