What is a common material used in high explosives, which also has applications in fertilizers?

Ammonium nitrate is a common material used in high explosives due to its ability to support rapid combustion as an oxidizer. This compound can enhance the detonation capability of various explosive formulations when blended with fuel, making it a critical component in many military and industrial explosives.

In addition to its explosive applications, ammonium nitrate is widely used in fertilizers because it provides essential nitrogen, which is vital for plant growth. This dual use underscores the importance of ammonium nitrate in both agricultural and explosive contexts, making it unique among the choices provided.

Water, sodium bicarbonate, and calcium carbonate do not possess the explosive characteristics that ammonium nitrate does and are primarily utilized in different applications—water as a solvent and coolant, sodium bicarbonate in baking and neutralization, and calcium carbonate mainly in construction and agriculture. Thus, ammonium nitrate stands out as the correct answer due to its specific role in both explosives and fertilizers.