Why does mr. wakatsuki ask how old the interrogator is? what point do you think he is trying to make?

Alloy of metals is the answer

It would be around the egyptian area.

In financial aspects, a depression is a sustained, long haul downturn in monetary movement in one or more economies. it is a more extreme monetary downturn than a recession, which is a slowdown in financial action through the span of a typical business cycle. a depression is an irregular and extreme type of recession. so depression is always followed by recession but it is not correct to state that a depression always follow a recession.