The answer is letter
D.
<span>
Communicable diseases
are also known as infectious or contagious diseases. They may come from food,
water, animals, another person, or anything that comes from the environment. <span>Airborne
viruses, bacteria, blood, and bodily fluids can cause the spread of these
diseases. The most common communicable disease is the flu, which can easily
spread in an enclosed environment with a recycled circulating air (e.g.
air-conditioning). Infectious disease caused by blood contact like HIV/AIDs are
also dominant in society. </span></span>
Pretty good! How about you? :D
Answer:
because you are using them and it because it your bones get tired
