In WWI, the was slow and unreliable, but effective.

Tanks.

Explanation:

During the world war I, the development of mass weapons of destructions still haven't reach the current state. So, the armies at that time still relied on automatic rifles/guns.

Tanks provide a very strong protection for this type weapons'

It provided a way for an army to pernitrate enemy's territory which filled with automatics turrets/riffles as their main source of protection. Compared to air planes, tanks were significantly slower. But it's still very effective to opened up a pathway to bring down a milltuiary base.

when a country suffers, for example, a drought period, the market product is affected for a low offer, in this case, potatoes; the government has to tax to the households, which have to give more money for the potatoes which they consume, that situation make them consume substitute goods even through loans, it could increase the financial market movement and the inflationary phenomena, the business has to increase salaries in order to the employees could buy a more expensive food (potatoes) and in order to inflation tha business had to buy expensive supplies in the factor market, while the rest of the world have to gain more money to consume the same amount of potatoes.