When discussing the key features of a linear graph, which of the following statements is true?

The true statement regarding the key features of a linear graph is:

**The points will make a straight line.**

In a linear graph, the relationship between the variables is constant, which means that the plotted points will form a straight line.

The other statements are not true in general:
- The initial value is not always zero; it can be any value depending on the equation.
- The rate of change is constant in a linear graph, not varying.
- The points do not always have positive values; they can be negative depending on the context of the graph.