What is the difference between an open and closed point for an inequality

What is the difference between an open dot and a closed dot on a number line?

How do you represent the inequality X < 2 on a number line?

Explain why the point 2 is not included when graphing X < 2.

What does it mean when an inequality is written as X ≤ 2?

How can you visually differentiate between open and closed dots on a graph?