What piece of farm equipment made it possible to open up the fertile lands of europe?

The correct answer is the plow.

Before the advent of plows, there was no method to utilize the land to its comprehensive scope. Spades couldn't harvest far immersed inside and it was kind of pointless, while plows were dragged by animals and horses way before the engine was designed. The sickle was just a large blade beneficial for reaping products but other things could be utilized too.

workers should be given a fair share of the wealth their work creates

hope this