What was a direct result of the bay of pigs invasion
in 1961?
(1) fidel castro was removed from power.
(2) cold war tensions increased.
(3) the united states announced its good
neighbor policy.
(4) the communist government in nicaragua was
overthrown.

A direct result of the Bay of Pigs invasion in 1961 was that "Cold War tensions increased", mainly because this put into question the boundaries of both states. 

It changes food into energy that the organism can use.

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.