Vice Pres
The Vice President will take the immediately responsibility.
Should the President die in office, or otherwise no longer be able to serve, then the Vice President moves up.
If Obama dies in office, his vice President, Joe Biden, becomes the next President.
The Vice President
If he dies in office, then Dick Cheney becomes President.
The vice president becomes the president if the president dies. Such is the main reason for the office of vice president.
If the president dies then the vice president takes office if the vice president dies then the speaker of office is president
The Speaker of the house becomes president
The Vice-President.
The vice president takes office if the president dies.
Nobody. A president continues to serve in office when he is impeached. If he is convicted and removed from office, the vice-president becomes president, same as if the president were to die.
The Vice-President rarely becomes President, and then it is usually because the previous President died while in office.