Answer:
Spinning a ball on a string or twirling a lasso: Here the centripetal force is provided by the force of tension on the rope pulls the object in toward the centre. Turning a car: Here the centripetal force is provided by the frictional force between the ground and the wheels.
Explanation:
The answer would be D)hormones
I would say the answer is D because just like in example, chicken pox is not always safe, and healthy kids in chicken pox party can also get infected and become very sick instead of just getting exposed to them. Vaccine however just basically gave us immunity to the disease without the getting sick step.