Natural selection: organisms with certain inherited traits that are more likely to survive and reproduce than others.
These favorable traits can give an organism an advantage by giving them a higher chance of survival and reproduction. Darwin called this, "survival of the fittest"
Answer:
The two ways are as metabolic waste that is product of respiration and --by living organism
Also
As a result of burning of either material or substance let's say from engine--non living matter
Answer: 22% Cytosine
If Thymine is at 28% and Thymine always pairs with Adenine (another compound that is one of four constituents of nucleic acids, often paired with Thymine in double-stranded DNA), then Adenine is also 28%. The remaining 44% will then be divided between Cytosine and Guanine (another compound) since they also form pairs.