time to make a fool of myself. the axis represent 2 goods/"opportunities", not supply and demand, because x1 and x2. There is no price or quantity.
um. well it looks like 3 PPF curves, the curve shape and the axis labeling suggest this. So this is a supply side indifference curve(wat)...because it's concave? I think it's supply side because it shows a high opportunity cost(concavity shows this. you have a FAST drop to gain one at the expense of the other, whereas in a convex curve it's gradual. landing a plane opposed to pushing a boulder off a cliff; decision vs force. this is circumstantial and a fairly layman explanation). People can more easily choose to substitute, but it takes a lot more resource, thought, and missed opportunities to switch factory production. Or it could be the most intense consumer opportunity cost ever...like are you going to cut off your left leg or right arm to gain the most utility?...
um. well, we know the curves are rational, because...because they dont criss-cross...
The curves on the right have a superior preference to the ones on the left...because bigger numbers there(this, this is econ)...and points further to the right of the right-most curve are preferred, but currently unattainable, or else there would be a curve there and would be factored in the present day calculation of indifference as opposed to being a projection.
was this all there was in the question? what is an acceptable answer? is the graph correct? I need an adult.