A. it is a survival reaction that helps us live when in dangerous situations
the fight or flight instinct is triggered when scared/in danger. you choose whether to fight, or run away.
you don’t think through options all the time with either running or fighting it. therefore, it’s A.
False. If you were to limit water intake then performance would be hampered.
For starters, you must live up to what you fight for, so adopting a healthy lifestyle is the first obvious step. Also, considering the absurdly broad scope of the "health" definition (from the WHO, for example), you would have to decide on a specific focus. (i.e. alternative medicine? Nutrition and fitness? Access to global healthcare? and so on).
Among the career paths you could pick, there are:
*Becoming a health educator, by writing or broadcasting TV/ Youtube shows on wiser health choices;
*Visiting countries where people lack basic resources in nutrition and diet, urban sanitary infrastructure, and/or healthcare advances (like vaccines); or perhaps other places where there has been a rise of non-trasmissive chronic diseases (e.g. obesity, hypertension, diabetes). The purpose is really to educate people on ways to overcome the causes and to bring awareness to the problems.
*And finally, you can be a personal trainer/dieter to individuals or groups.
I hope this helps!