.......................... is invariably a component of amino acids, nucleic acids and chlorophylls.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Components:**
- The question asks for a component that is found in amino acids, nucleic acids, and chlorophyll. We need to identify a common element or compound present in all three.

2. **Analyzing Amino Acids:**
- Amino acids are the building blocks of proteins. Each amino acid contains an amino group (-NH2), which includes nitrogen. Therefore, nitrogen is a key component of amino acids.

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