Explain rationally what happens in reality. Include terms like demand, supply, variable and fixed costs, marginal or incremental changes, marginal and average costs, price elasticity, income elasticity, maximization, minimization, normal profit, competitive markets, product differentiation, market structure, oligopoly, and other relevant terms.

An Analysis of COVID-19 Pandemic and Retail Sales of Consumer Goods

Explain rationally what happens in reality. Include terms like demand, supply, variable and fixed costs, marginal or incremental changes, marginal and average costs, price elasticity, income elasticity, maximization, minimization, normal profit, competitive markets, product differentiation, market structure, oligopoly, and other relevant terms.