To determine the slope of the line, we can use the slope formula, which is:

$m = \frac{y_2 - y_1}{x_2 - x_1}$

Here, the two points on the line are $(-3, -1)$ and $(3, 1)$.

Substituting these coordinates into the formula:

$m = \frac{1 - (-1)}{3 - (-3)} = \frac{1 + 1}{3 + 3} = \frac{2}{6} = \frac{1}{3}$

Thus, the slope of the line is $\frac{1}{3}$.

Would you like more details or have any questions about this? Here are five related questions you might find useful:

1. What does a positive slope indicate about the direction of the line?
2. How would you calculate the slope if the points were given in different quadrants?
3. How can you use the slope to determine if two lines are parallel?
4. What is the slope of a horizontal or vertical line?
5. How can you write the equation of a line once you know the slope and a point on the line?

Tip: The slope of a line tells you how steep the line is and the direction it slants.