Solution
= Solution
The independence fails after conditioning on $S=1$. Since $S$ is a descendant of collider $M$, selection opens $D\to C\to M\leftarrow A\leftarrow G$.
= Solution
The independence fails after conditioning on $S=1$. Since $S$ is a descendant of collider $M$, selection opens $D\to C\to M\leftarrow A\leftarrow G$.