This document discusses consumer choice and how consumption changes in response to changes in price and income. It covers: - When prices increase, quantity demanded decreases as consumers adjust to a new optimal point along a pivoted budget line. - Income-consumption and price-consumption curves show the relationship between these variables and consumption of a good. - Normal goods have positive relationships, while inferior goods have negative relationships between income/price and quantity. - Price changes cause substitution and income effects that shift consumption, and elasticity measures the responsiveness of quantity to price and income changes.