Select two of the following roles performed by U. S. president:

Please help!

Chief Executive-As Chief Executive the president can: implement policy, supervise the executive branch of government, prepare executive budget for submission to congress, and appoint and remove executive officials. The head of government is the chief officer of the executive branch of a government, often presiding over a cabinet.

Commander in Chief-A commander-in-chief or supreme commander is the person who exercises supreme command and control over an armed forces or a military branch. As a technical term, it refers to military competencies that reside in a country's executive leadership, a head of state or a head of government.

Explanation:

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.