Signal theory is related to

Options

A. Nervous system
B. Emergency
C. Formation of special membrane lipids
D. Synthesis of secretory proteins.

Answer

**Step-by-Step Solution:**

1. **Understanding Signal Theory**: Signal theory refers to the mechanisms by which cells communicate with each other and respond to external stimuli. This is a crucial aspect of biological systems.

2. **Identifying the Options**: The question provides four options:
- Nervous system
- Emergency
- Formation of special membrane lipids
- Synthesis of secretory proteins

3. **Analyzing Cell Signaling**: Cell signaling is essential for various cellular functions, including development, growth, and immune responses. It allows cells to perceive their environment and respond accordingly.

4. **Linking to Secretory Proteins**: Among the options, the synthesis of secretory proteins is directly related to cell signaling. Secretory proteins are often produced in response to signals from other cells or the environment.

5. **Conclusion**: Therefore, the correct answer to the question is that signal theory is related to the synthesis of secretory proteins.

**Final Answer**: Signal theory is related to the synthesis of secretory proteins.

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