Answer:
C: waste.
Step-by-step explanation:
I think you are in the wrong section. But the answer is
C: Waste.
A: Disease is mostly fought by the neutrophils, a type of white blood cell that's a warrior when it comes to fighting disease.
B: energy. I'm not exactly sure who provides the energy. The first step is the digestive system.
D: Oxygen is again a blood thing. The hemoglobin caries oxygen to various parts of the body.