Final answer:
The correct answer to what is one-dimensional with length but no width or height is B) Line. A line is indeed one-dimensional, extending infinitely in both directions with only the dimension of length.
Step-by-step explanation:
The correct answer is option B) Line. A line is a geometric object that has length but no width or height, making it one-dimensional. In mathematics, the concept of a line extends infinitely in both directions and is often described by a set of points that satisfy a linear equation. The length is a measure of one dimension of an object, and when referring to one-dimensional objects in mathematics, a line is a perfect example because it only has this single dimension of length. Lines are fundamental components of geometry and are used to represent objects and concepts which are straight and have an unchanging direction.
A line is considered one-dimensional because it has length but no width or height. It is a straight path that extends infinitely in both directions. An example of a line in real life is a ruler or a railway track.