The answer would be D. Frequent infections.
If you are a smoker quit smoking. Eat three meals a day, doesn't mean you have to eat a lot. Eat alot of vegetables and fruits - at least 1/4 cup worth a day. Avoid processed/canned fruits as they most likely added sugar to it. Exercise daily at least half an hour a day. Stay hygienic. Eat more proteins than junk food. Lessen the amount of snacks a day to 1-2 each should be 100 cals or below. Avoid eating a lot of carbs as it can raise insulin and make you feel hungry often.
Motivational quotes, finding things you enjoy doing and learning to ignore people who are negative. Also learning about Jesus could help as well (:
Excitatory neurotransmitter? This question is too vague.
