Help me someone i nedd the answe really bad

The percent efficiency of a machine can never be 100% (or greater), because in the real world some energy is always converted into a. heat b. work c. input force d. output force

Will you chech and finish these for me, because i am stumped with them.

Velocity is a description of both speed and direction, therefore it - a vector - a force arrow - the same as acceleration - a magnitude