Signs of social health = spending time with friends
Signs of physical health = eating a nutritious diet
Signs of emotional health= enjoying hobbies
Explanation: Social health relates to people which would include spending time with friends makes sense. Physical health relates to eating and exercising so eating a nutritious diet makes sense. Emotional health relates to the state of how you feel emotionally and you can take care of yourself by participating in activities you enjoy like enjoying hobbies.
I believe the answer is: Eat a well-balanced diet to increase energy and immunity
Even though physical activities improve both our energy and immunity in the long run, they are not as significant as maintaining well balanced diet in your life.
You need to make sure that you get your nutrients from various source of non-processed food in order to fulfill both your macronutrients and micronutrients.