To answer the question about naming the line and plane in the diagram:

1. Line: The line shown in the diagram passes through points $R$ and $S$. Therefore, the line can be named as line $RS$ or $\overleftrightarrow{RS}$.

2. Plane: The plane contains the points $R, S, U,$ and $T$. A plane can be named using any three non-collinear points on it. For this diagram, the plane can be named as plane $RST$, plane $RSU$, or any combination of three points like $\text{plane } RUS$ etc.

Would you like more details or have any specific questions?

Here are some related questions that might help expand your understanding:

1. What does it mean for points to be collinear?
2. How do you determine if a point lies on a line or plane?
3. What are the different ways to name a line in geometry?
4. Can a line lie outside a plane in three-dimensional space?
5. How do we represent the intersection of two planes?

Tip: In geometry, when naming a plane, make sure that the points chosen are non-collinear, as three collinear points do not uniquely determine a plane.