Q1. Within which sections of the production function is marginal product increasing?

Q2. Explicate the link between scarcity, choice and opportunity cost?

Q3. "The potentially valid arguments for tariff protection military infant business security, self sufficiency as well as diversification for steadiness are also the most easily abused." Why are these arguments susceptible to abuse?

Q4. People join tennis clubs for a fixed fee for every year that allows them to play as much as they want without charge. It is because person who deposit these fees play more tennis than others who can use free public courts which means sunk costs matter for decisions?