Decide Whether or Not the Matrix Is a Transition Matrix $\left[\begin{array}{rr}0.7 & 0 \\ 0 & 0.3\end{array}\right]$

Decide whether or not the matrix is a transition matrix.
- $\left[\begin{array}{rr}0.7 & 0 \\ 0 & 0.3\end{array}\right]$