What doesn't limit the range of moton from the things which you've mentioned would be age. Age per se doesn't really limit the range of motion - while there are factors which negatively influence our range of motion and which are strongly correlated with age, it is hard to say that age itself would be the cause of a limited range of motion.
She likes the word contagious because many good things are contagious like laughter and passion and <span>inspiration. Also the word shows that one good idea can become contagious and change the world SOURCE ANSWER KEY :))</span>