Suppose Vincent decides to plant the poppies. Which result would be a cost?
Vincent will give up the chance to look at the eucalyptus tree. He thinks it would have looked more beautiful than the poppies. He will save some space. The poppies will use up less space than the eucalyptus tree would have used up.
Vincent is deciding whether to plant poppies or a eucalyptus tree in his backyard. He wants to make his backyard more beautiful. But he also wants to leave space for doing fun things.
Before you decide to do something, it is often helpful to list costs and benefits.
Costs are what you give up or spend when you decide to do something. Costs involve giving up things that you want or need.
Benefits are what you gain or save when you decide to do something. Benefits involve gaining something that you want or need.
This result is a cost. It involves giving up or spending something that Vincent wants or needs:
Vincent will give up the chance to look at the eucalyptus tree. He thinks it would have looked more beautiful than the poppies.