Final answer:
In Mathematics, linear elements are represented by lines. Nodes refer to points on the line with no probability of finding an electron, making them the correct answer option.
Step-by-step explanation:
In Mathematics, linear elements are represented by lines. A line is the most basic visual element that can be used to define shapes, indicate motion, and create forms.
In this context, nodes can refer to points on the line where there is no probability of finding an electron, while edges can represent the paths or lines themselves. Therefore, the correct answer is a. Nodes.