Question

atmospheric layers quick check
why is it harder to breathe when climbing up a high mountain? (1 point)
○ the air is thinner.
○ the air pressure increases.
○ the air compresses the lungs.
○ the air has more moisture.

Explanation:

To determine why it's harder to breathe at high altitudes, we analyze each option:

• "The air is thinner": At higher altitudes, the atmosphere has less air molecules per unit volume (thinner air), so there's less oxygen available, making breathing harder. This is correct.
• "The air pressure increases": Air pressure decreases with altitude, so this is incorrect.
• "The air compresses the lungs": There's no mechanism for air to compress lungs in this context; lung function is affected by oxygen availability, not air compressing lungs. Incorrect.
• "The air has more moisture": Moisture in air generally decreases with altitude, and moisture alone doesn't make breathing harder in this scenario. Incorrect.

Answer:

The air is thinner.