Answer:
The correct answer is "C-to-T transition".
Explanation:
When cytosine is hydrolysed or methylated it could result in the formation of an uracil via the deamination of cytosine. The uracil that is formed in the genomic DNA could be repaired by DNA repair pathways, but it could result in the formation of a tyrosine. These series of mutations are known as "C-to-T transition" because it starts with a cytosine and ends with a tyrosine. This kind of somatic mutations are very studied because they had been found in human breast tumors.
Cccccccccccccccccccccccccccccc
Answer: ecosystem
An ecosystem is a community of living and non-living components. A coral reef is an aquatic ecosystem which is formed by a continuous walls of calcium carbonates released by living animals they get combine to form rocks. These rocks and walls are collectively called as hard stony corals. These hard stony corals provide shelter to many aquatic animals like fishes. As the water is the chief abiotic factor along with coral walls and rocks which help in the survival of living organisms therefore, ecosystem is the largest organizational level found in one coral reef.