To solve the question regarding the correct match of a drug, its source, and its action, we will analyze each option step by step.
### Step 1: Analyze Morphine
- **Source**: Derived from the latex of Papaver somniferum (opium poppy).
- **Action**: It is known to depress brain activity.
- **Conclusion**: While the source is correct, the action is incorrectly described as an "effective stimulant." Morphine is a depressant, not a stimulant. Therefore, this option is incorrect.
**Hint**: Remember that morphine is primarily used for pain relief and has depressant effects on the central nervous system.
### Step 2: Analyze Cocaine
- **Source**: Derived from Erythroxylum coca (coca plant).
- **Action**: The statement claims that high levels do not cause hallucinations.
- **Conclusion**: This is incorrect because high doses of cocaine can indeed lead to hallucinations. Therefore, this option is also incorrect.
**Hint**: Cocaine is a powerful stimulant that can lead to various psychological effects, including hallucinations at high doses.
### Step 3: Analyze Heroin
- **Source**: Produced from the acetylation of morphine.
- **Action**: The statement claims it is used to reduce pain.
- **Conclusion**: While heroin does have pain-relieving properties, its primary action is to slow down body functions and can lead to significant respiratory depression. Thus, the action described is misleading. This option is incorrect.
**Hint**: Heroin is often misused for its euphoric effects, but it significantly depresses the central nervous system.
### Step 4: Analyze Barbiturates
- **Source**: Derivatives of opium (though more accurately, they are synthetic drugs used for sedation).
- **Action**: The statement claims they depress brain activity and produce feelings of calmness, relaxation, and drowsiness.
- **Conclusion**: This description is accurate. Barbiturates do depress the central nervous system and are used for their sedative effects. Therefore, this option is correct.
**Hint**: Barbiturates are often used in medical settings for their sedative and anesthetic properties.
### Final Conclusion
After analyzing all options, the correct match regarding the drug, its source, and its action is **Barbiturates**.
**Correct Answer**: Option 4 - Barbiturates (derivatives of opium), which depress brain activity and produce feelings of calmness, relaxation, and drowsiness.
