1. The problem statement, all variables and given/known data What exactly does it mean for a surface to span a contour/curve? For example, which surface(s) span the contour/curve defined by the equations x^2 + y^2 = 1 and z = y^2? 2. Relevant equations N/A 3. The attempt at a solution I'm not sure if I'm saying something nonsensical, but does any surface that covers at least the contour/curve in question span it? Would a cylinder as well as a sphere each span the contour curve defined by the equations x^2 + y^2 = 1 and z = y^2?