Final answer:
The characteristic not associated with elastic demand is that the commodity is a necessity good. Elastic demand is indicated by high price sensitivity, significant changes in quantity demanded due to price changes, and the availability of substitutes.
Step-by-step explanation:
The student's question relates to the characteristics of the elastic demand for a commodity. Elastic demand occurs when the elasticity of demand is greater than one, indicating a high responsiveness to changes in price. A commodity with elastic demand will show a large change in quantity demanded with a small price change, suggesting that the consumer has high price sensitivity and that there are alternatives or substitutes readily available.
However, if the commodity is a necessity, the demand is likely to be inelastic since consumers will continue to buy it despite price changes. Therefore, the characteristic that is not associated with elastic demand is that the commodity is a necessity good. The availability of substitutes and the significant changes in quantity demanded due to price changes, along with high sensitivity to price, are key features of elastic demand.