Tradeoffs promote socioeconomic goals. Tradeoffs increase efficiency. Opportunity costs are always associated with tradeoffs. Opportunity costs are sometimes associated with tradeoffs. Opportunity costs are never associated with tradeoffs.
Opportunity costs are the opposite of tradeoffs.
The opportunity cost of dieting is the same for everyone. The opportunity cost for any action will be different for different people. The opportunity cost of private actions are different for every person, but the opportunity costs of government actions are the same for everyone. The price of a good becomes higher as more of the good is produced. The price of a good becomes higher as more people want to buy it.