This document discusses key concepts related to demand in microeconomics, including: 1. Demand refers to the desire and willingness to pay for a product. It is influenced by factors like income, tastes, substitutes, expectations, and number of consumers. 2. The law of demand states that as price increases, quantity demanded decreases, and vice versa. This inverse relationship is shown on a demand curve or schedule. 3. Elasticity of demand measures how responsive quantity demanded is to changes in price. Demand is more elastic if close substitutes exist or a product is a luxury versus necessity.