General Information. A brief introduction about the caffeine.​

A central nervous system stimulant

Explanation: arguably the most frequently ingested pharmacologically active substance in the world.

Caffeine, a central nervous system stimulant, is arguably the most frequently ingested pharmacologically active substance in the world. Occurring naturally in more than 60 plants, including coffee beans, tea leaves, cola nuts, and cocoa pods, caffeine has been part of innumerable cultures for centuries.

Explanation:

A hydrogen ion is called a proton because hydrogen ions lose their one electron and are only composed of one proton.