The three ways mutations can occur are
Mutations arise spontaneously at low frequency owing to the chemical instability of purine and pyrimidine bases and to errors during DNA replication. Natural exposure of an organism to certain environmental factors, such as ultraviolet light and chemical carcinogens (e.g., aflatoxin B1), also can cause mutations.
Answer:
The layer of Earth's atmosphere where atoms and molecules escape into space is referred to as the exosphere. :)
Answer: B. S cycle
Explanation: The S phase of a cell cycle occurs during interphase, before mitosis or meiosis, and is responsible for the synthesis or replication of DNA.