You always have to warm up, if you start to over exert yourself without a warm up you could get hurt
You can prevent the spreading of communicable disease by following through with Option C) avoiding sharing personal items, like toothbrushes. All of the other options can lead you to getting a disease, if you ignore hygiene you will never be clean, and if you avoid insect repellent you might get a disease from a bug, and if you cough/sneeze without covering your nose/mouth then you may catch a cold. Therefore pointing to the correct answer option C.
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Answer:
The thymus lies in the chest behind the breastbone and above the heart. Relatively large in infancy, it increases in size until puberty and thereafter shrinks to only a few grams in old age.
Explanation: