Answer:
virus
Explanation:
viruses are the smallest type of pathogen
Being underweight can contribute to a very frail and weakened immune system. It can make one feel tired mentally. And can also affect the bones by making them very brittle and frail sometimes.
Deficit of insulin, higher levels of glucose
Number 3 would be the best. It's never a good idea to cut ALL fats and sugars, because you need them for energy.
