Explanation:

The classical growth theory argues that economic growth will decrease or end because of an increasing population and limited resources. Classical growth theory economists believed that temporary increases in real GDP per person would cause a population explosion that would consequently decrease real GDP.
Economists behind classical growth theory developed an idea of a "subsistence level" to model the theory. Subsistence refers to the minimum amount of income required to survive. Income beyond the subsistence level translated to profits. Related to this concept was the manner in which different classes within society utilized their wages. For example, workers spent their wages on subsistence, landlords spent their earnings on "riotous living," and industries reinvested their profits into their ventures.