Final answer:
According to economic-buyer theory, people choose what to buy based on utility or satisfaction needs. Greater consumption of a good brings higher total utility, but the additional utility from each unit tends to decline in a pattern of diminishing marginal utility.
Step-by-step explanation:
According to economic-buyer theory, people choose what to buy based on utility or satisfaction needs. Utility refers to the satisfaction or pleasure that individuals derive from consuming a good or service. It is believed that greater consumption of a good generally brings higher total utility, but the additional utility received from each additional unit tends to decline in a pattern of diminishing marginal utility. This means that the first unit of a good provides more satisfaction than subsequent units.