The primary emphasis in macroeconomics is on:

marginal analysis

bits and pieces of the economy

the national economy

how firms set prices

Scarcity in economics means:

not having sufficient resources to produce all the goods and services we want

the wants of people are limited

shortages exist in nearly all markets

there must be poor people in rich countries

A key theme fundamental to all of economics is:

there are unilimited resources

people have unlimited wants facing limited means to satisfy them

there are limited wants

we are a rich country but are simply not aware of it