In the American constitutional system, the legislative branch makes the law, the executive branch executes the law, and the judicial branch interprets the law. How does this system support the separation of powers?

Each branch has separate tasks, Congress grants power based on those tasks, and power is not shared between branches.
Each branch's role is separate, power is shared between branches, and the president can challenge a branch's decision.
Each branch affects the other, power is shared, and one branch can be challenged by another branch.
Each branch has a specific role, the president gives power to each branch, and the powers cannot be challenged by another branch.