At high altitudes, more time is required to cook food because the boiling point of water is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Less than 100° C
A liquid boils when its vapour pressure equals the pressure of the air above it, so the boiling point falls when the air pressure falls. At high altitudes the air is thinner and its pressure is lower, so water boils below 100 °C (at about 3,500 m, near 88 °C). The water never gets as hot as it does at sea level, so food takes longer to cook.
Why the other options are incorrect
Option (2) More than 100° C — Incorrect. Water boils above 100 °C only under higher pressure, as in a pressure cooker, which is why a pressure cooker helps in the hills.
Option (3) Less than 98° F — Incorrect. 98 °F is about 37 °C, body temperature; water does not boil that low at any height where people live.
Option (4) More than 200° C — Incorrect. The boiling point falls with height; it does not rise, let alone to 200 °C.