40 to 500 mg of theobromine per 100 grams of chocolate. Theobromine stimulates smooth muscle and accelerates nerve conduction. But unlike caffeine, theobromine has almost no effect on the central nervous system. Every 100 grams of chocolate contains 70 mg of caffeine. The role of caffeine is to improve alertness. It promotes people's extraordinary performance, improves observation, resists fatigue, and improves the efficiency of mental activity. Chocolate also contains amphetamine. It also has a refreshing effect and can stimulate the hypothalamus Norepinephrine secretion. What does this text mainly explain? ['Chocolate has a role in promoting nerve excitement.', 'Chocolate and coffee have different effects on the human body.', 'Theobromine is more beneficial to the body than caffeine.', 'Caffeine affects the central nervous system of the human body.']