To answer the question "Set U in roster form," we need to identify all the elements inside the universal set $U$ in the provided Venn diagram. The universal set $U$ consists of all elements within the diagram, regardless of whether they belong to sets $A$, $B$, or $C$.

From the Venn diagram, we can list the elements of $U$:

$U = \{1, 4, 5, 7, 8, 13, 19, 21, 22, 23, 25, 28, 29, 30\}$

So, the roster form of $U$ is:

$U = \{1, 4, 5, 7, 8, 13, 19, 21, 22, 23, 25, 28, 29, 30\}$

Would you like further details or explanations on Venn diagrams or set theory?

Here are 5 related questions:

1. What is the difference between a universal set and subsets in set theory?
2. How do you identify the union of two sets using a Venn diagram?
3. Can a set be a subset of itself?
4. How is the intersection of two sets represented in roster form?
5. What are some real-life examples of using Venn diagrams?

Tip: When writing a set in roster form, make sure that all elements are distinct and listed only once, even if they appear in multiple regions of the Venn diagram.