Final answer:
The surface represented by the equation z = 7 - y² is a downward-opening parabolic surface.
Step-by-step explanation:
A downward-opening parabolic surface typically refers to the graph or geometric shape formed by a quadratic function of the form y=ax^2+bx+c, where a is a coefficient that determines the direction and steepness of the parabola. The surface represented by the equation z = 7 - y² is a downward-opening parabolic surface. The vertex of the parabola is located at (0, 7) and the axis of symmetry is the y-axis. The surface opens downward because the coefficient of y² is negative.