what is scarcity definition of economics?

Economics is essentially the study of economic problems that
we must confront owing to the fact that our means are scarce in
relation to our wants, and that the means have alternative uses. If
there is no scarcity, there is no economic problem, and there is no economics
if there is no economic problem. Thus, Robbins defines economics as
“a science that studies human behaviour as a relationship between ends
and scarce means which have alternative uses.”