Why do high altitude areas have brighter sunlight and lower temperatures as compared to the plains?

At high altitudes , water boils at a lower temperature because

At high altitudes, water boils at a lower temperature because

Assertion : At high altitudes liquids boil at lower temperaturers in comparison to that of sea level. Reason : At high altitudes atmospheric pressure is low

Assertion : At high altitudes , liquids boil at lower temperatures in comparison to that at sea level . Reason : At high altitudes , atmospheric pressure is low .

At high altitudes the boiling point of water gets lowered because

Water boils at lower temperature on higher altitudes because