Which abiotic factor has role in setting or resetting the biological clocks?

Options

A. Light
B. Pressure
C. Gravity
D. Soil

Answer

**Step-by-Step Solution:**

1. **Understanding Biological Clocks**: Biological clocks are internal mechanisms that regulate various physiological processes in organisms, including circadian rhythms, which dictate sleep-wake cycles and other daily activities.

2. **Identifying Abiotic Factors**: Abiotic factors are non-living chemical and physical components of the environment that affect living organisms. Examples include light, temperature, soil, gravity, and atmospheric pressure.

3. **Role of Light in Biological Clocks**: Among the abiotic factors, light plays a crucial role in setting or resetting biological clocks. It influences the circadian rhythms of both plants and animals. For instance, exposure to light signals the body to wake up and become active, while darkness signals rest and sleep.

4. **Eliminating Other Options**: The other abiotic factors listed (soil, gravity, and pressure) do not have a significant role in regulating biological clocks. They may affect other physiological processes, but they do not directly influence the sleep-wake cycles or circadian rhythms.

5. **Conclusion**: Therefore, the abiotic factor that has a role in setting or resetting biological clocks is **light**.

**Final Answer**: Light

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