The jet aircraft fly very easily and smoothly in the lower stratosphere. What could be the appropriate explanation? Which of the statements given above is/ are correct in this context?

Answer: (c) Both I and 2

Both make flying smooth.

Statement by statement

1. ✓ CORRECT The lower stratosphere has almost no clouds or water vapour.

2. ✓ CORRECT There is little vertical air movement — so no turbulence.

The idea

Stable air resists vertical displacement. In the lower stratosphere, temperature generally rises upward, so a lifted parcel tends to be cooler than its surroundings and sink back. This limits convection and most weather clouds. Stability means smoother conditions on average, not a guarantee of zero turbulence.

Ozone absorbs ultraviolet energy → Stratospheric temperature rises with height → A displaced parcel is relatively cool → Buoyant ascent is suppressed → Most weather clouds remain below → Flight conditions are often smoother

Why the others are wrong

(a) Drops the lack of vertical winds.

(b) Drops the lack of clouds.

Also know

Aircraft cruise near the tropopause or lower stratosphere depending on route and latitude. Jet streams occur near the tropopause and can create clear-air turbulence. Water vapour is scarce in the stratosphere, not wholly absent. Polar stratospheric clouds can form in exceptionally cold conditions and play a role in ozone loss.