The answer to that is sunlight. If you need an explanation tell me but I think it’s self explanatory :)
Answer:
James Watson and Francis Crick solved the structure of DNA. Rosalind Franklin and Maurice Wilkins, also contributed to this discovery.
Explanation:
The substrate of the citric acid cycle which can block respiration when it is present in excess is MALONATE. Malonate inhibits respiration by competing with succinate dehydrogenase for its acitve site. Malonate binds to the active site without reacting, thus competing with succinate. This disrupts the cellular respiration in the cell.