1. Three resistors $R_1, R_2$, and $R_3$ are connected as shown below.

The resistance of $R_3$ is $1 \Omega$ and it is known that the value of $R_3$ is smaller than the values of $R_1$ or $R_2$. The resistances of $R_1$ and $R_2$ are unknown.

Select the best statement describing the equivalent resistance of this combination: