Like an example?
if an example it can be
<span>Alzheimer's disease</span>
While you didn't provide any following sources, healthy sources of energy for humans are usually considered to be different types of fruits and vegetables, lean meats, wholewheat grains, nuts, seeds, and healthy oils. All these constitute a healthy human diet and are a healthy source of energy.
White blood cells help to fight infection
The blood carries these cells
