What is the difference between demand for vegetables and tobacco products?

The difference between demand for vegetables and tobacco products is the income elasticity of demand, which  measures the relationship between a change in quantity demanded for good X and a change in real income. Vegetables are normal goods. They have a positive income elasticity of demand so as consumers' income rises more is demanded at each price. Tobacco products on the other hand are inferior goods because they have negative income elasticity of demand which means that demand falls as income rises.