What's the questions here ?
The correct answer is - underwater mountain ranges.
The mid-ocean ridges are actually underwater mountain ranges, which usually are very long, in fact the longest mountain range on Earth is created on the divergent boundary between the Eurasian and North American tectonic plates and between the African and South American tectonic plates. At the divergent tectonic boundaries we have the creation of new crust which rises from the mantle and fills in the gap between the tectonic plates. Because of the big amount of magma and high pressure, very big and long underwater mountain ranges are formed.
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.