Incomplete question. However, I inferred you want an explanation of the term effective demand.
Step-by-step explanation:
Effective demand refers to an economic condition where a market experiences a constant demand to buy goods available for supply irrespective of how much they cost.
Or from the Keynesian view, it is the point of equilibrium (where aggregate demand = aggregate supply).
Income plays a role in determining an individual's effective demand, for example, when a person's monthly earnings increase, they are more likely to increase their spending; leading to effective demand.