The matter a wave travels through is called the material of the wave.

The energy of a mechanical wave can travel only through matter. The matter through which the wave travels is called the medium (plural, media). The medium in the water wave pictured above is water, a liquid.

There is none!

Explanation:

In a Communist system, the central authority dictates the means and quantity of production, and places strict rules on businesses.

Since there is no competition amongst firms, each is given the same amount of money and each worker is paid the same, with the same expectations of each.

All businesses are ultimately owned by the government.

Populations tend to be treated homogeneously, meaning that common goals or sets of rules will not apply to different segments of the population and community.

Without a price mechanism, supply and demand are difficult to balance perfectly over time.

If you dont follow them you will die.