Final answer:
The mild stimulant found in coffee, tea, and several plant-based substances is caffeine. It blocks adenosine activity to help you feel more awake and alert. An effective dose is about 200 mg.
Step-by-step explanation:
The mild stimulant found in coffee, tea, and several other plant-based substances is caffeine. Caffeine functions as a central nervous system stimulant, making individuals feel more awake and alert. It is thought to block the activity of adenosine, a neurotransmitter that carries messages between nerve cells, thus preventing drowsiness. An effective dose of caffeine is typically around 200 mg, which is roughly equivalent to two cups of strong coffee or tea. It's important to know that while caffeine is widely consumed and can be beneficial in moderate amounts, excessive intake may lead to undesirable side effects.