Question

1. choose the best answer.

the ___ of a parabola is the line, along with a point not on the line, which is used to generate a parabola.
focus
directrix
vertex
parabola

Explanation:

A parabola is defined as the set of all points equidistant from a fixed point (the focus) and a fixed line (the directrix). The problem mentions a line (which is the directrix) and a point not on the line (the focus). The vertex is a point on the parabola, and "parabola" is the curve itself, not the line used in its definition.

Answer:

B. directrix