Caffeine is also a what? opioid narcotic barbiturate psychoactive

Opiod are drugs which are mainly used to relieve pain or in other words they have effects similar to those of morphine. Narcotic are drugs which are similar to opiods that affect moods and the behaviour of an individual, most of them are illegal. On the other hand, barbiturate are drugs mostly used to relax the body, treat insomnia and seizures. Lastly psychoactive drugs are those that cause changes in the brain in terms of mood, perception and behaviour among others.Therefore caffeine is psychoactive drug which acts as a stimulant mostly used to stimulate the brain and causes mood and behavioral changes.

Wind causes waves to form

The answer would be sand and gravel