Distinguish antagonists and agonists.

Explanation

To distinguish between antagonists and agonists, we can break down the definitions and functions of both types of drugs step by step.

### Step-by-Step Solution:

1. **Definition of Agonists**:
- Agonists are drugs that bind to specific receptors on cells and mimic the action of natural messengers (like hormones or neurotransmitters).
- When an agonist binds to a receptor, it activates the receptor and initiates a physiological response within the cell.

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