The right answer is agility.
You already have balance when you can stand on one foot, what you need is agility to turn quickly.
Agility is the ability to quickly change the position of one's body. This requires a combination of scales, psychomotor coordination, and reflexes.
The correct answer is C.
An author's credentials can determine a health source's credibility. None of the other options would apply to credibility. When it comes to health, if you want to make sure that what you are researching or reading is authentic and reliable you need to find out whether the author is a professional health expert or not. You can do this by finding out their credentials.
There are two definitions on which way you are saying stress.
pressure or tension exerted on a material object or a state of mental or emotional strain or tension resulting from adverse or very demanding circumstances.
