_________is mainly found in its free state in the atomosphere , more than three-fourths of which is composed of this element.

Options

A. Nitrogen
B. Carbon
C. Oxygen
D. Kypton

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for an element that is mainly found in its free state in the atmosphere and constitutes more than three-fourths of the atmospheric composition.

2. **Identifying Atmospheric Composition**: We know that the Earth's atmosphere is made up of various gases. The major components include nitrogen, oxygen, argon, carbon dioxide, and others.

3. **Analyzing the Composition of Nitrogen**: Among these gases, nitrogen is the most abundant. It makes up approximately 78% of the Earth's atmosphere.

4. **Comparing with Three-Fourths**: Three-fourths can be represented as 75%. Since 78% (the percentage of nitrogen in the atmosphere) is greater than 75%, nitrogen fits the criteria of being more than three-fourths of the atmospheric composition.

5. **Conclusion**: Therefore, the element that is mainly found in its free state in the atmosphere and constitutes more than three-fourths of it is nitrogen.

**Final Answer**: Nitrogen

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