**Step-by-Step Solution:**
1. **Understanding Gastric Glands**: Gastric glands are located in the stomach and are responsible for the secretion of gastric juice, which is essential for digestion.
2. **Components of Gastric Juice**: The gastric juice contains several components, including hydrochloric acid (HCl), pepsin, lipase, mucus, and bicarbonates. Each of these components plays a specific role in the digestive process.
3. **Role of Hydrochloric Acid (HCl)**: HCl is crucial for creating an acidic environment in the stomach, which helps in the digestion of food and also kills harmful microorganisms.
4. **Function of Pepsin**: Pepsin is an enzyme that breaks down proteins into smaller peptides. It is activated in the acidic environment created by HCl.
5. **Function of Lipase**: Lipase is another enzyme present in gastric juice that aids in the digestion of fats.
6. **Role of Mucus and Bicarbonates**: Mucus protects the stomach lining from the corrosive effects of HCl, while bicarbonates help to neutralize excess acid, ensuring that the stomach lining remains safe.
7. **Identifying Incorrect Options**: Among the options provided, renin is an enzyme that is primarily found in infants for the digestion of milk and is not present in adults. Therefore, it is not an appropriate component of gastric secretion in adults.
8. **Conclusion**: The most appropriate components of gastric secretion in adults include mucus, lipase, hydrochloric acid, bicarbonates, and pepsin.
**Final Answer**: The correct answer is the combination of mucus, lipase, hydrochloric acid, bicarbonates, and pepsin.
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