Friction is harmful because if your riding and you suddenly stop the friction will make you keep going forward and you'll fall super hard on the concrete(my experience).You also lose your balance. Friction is helpful because it prevents you from hitting cars and pedestrians.
B) Frequency of infectious illnesses usually increases as children grow older.
Answer:
The correct answer is - option D.
Explanation:
Cheilitis is a condition that cause the inflammation which affect the mouth and oral commissures in the corners that are caused by various health condition or disease. In this case Bertha is experiencing similar condition which is indefinite in this case, however it could be temporarily.
These condition also known as the stomatitis which should be clean with the oral swab to frequently by the nurse.
Thus, the correct answer is - option D.