...respiration!
Respiration is the biochemical process in which the cells of an organism obtain energy by combining oxygen and glucose, resulting in the release of carbon dioxide, water, and ATP (the currency of energy in cells). Source: https://study.com/academy/lesson/what-is-respiration-definition-process-equation.html
I hope that helps! :)
Natrual variations i think
Answer: B. Melting temperatures of primer should be between 55-80 degree Celsius.
Explanation:
Bacause the melting temperature controls the binding of the primers to your template DNA. At melting temperature 50% of the primer molecules are bound to their corresponding target sequence. If the difference in melting temperature between the two primers is too high, it might be difficult to find experimental conditions where both primers can bind to their target.