Efficiency is  The percentage of energy lost to the surroundings as heat

The percentage of energy actually used to perform the work

The entire amount of energy

The time it takes for half the energy to be used 

Asap many people try to eliminate fat from their diets which is one reason it is necessary for humans to eat fat a) fat is the only way to get energy b) every cell in the body must contain fat c)fat stores less energy than polysaccharides d) saturated fats make blood vessels healthier