Because of the cost of a taxi ride increased martha decided to start packing a lunch instead of ordering out from a nearby restaurant. which economic principle does this demonstrate?

The Cost of Something is What You Give Up to Get It

This means she gives up going out to be able to grab a taxi instead of transport such as Bus or Subway.

no one should discriminated against because he or she is not from a minority group

could you go a bit more in depth with you question? it's quite hard to understand. as soon as you do that i will be glad to : )