A layer in the Earth's atmosphere called Ionosphere facilitates radio communication. Why? 1. The presence of ozone causes the reflection of radio waves to Earth. 2. Radio waves have a very long wavelength. Which of the statements given above is/are correct?

La Nina is suspected to have caused recent floods in Australia. How is La Nina different from El Nino? 1. La Nina is characterised by unusually cold ocean temperature in equatorial Indian Ocean whereas El Nino is characterised by unusually warm ocean temperature in the equatorial Pacific Ocean. 2. El Nino has adverse effect on south-west monsoon of India, but La Nina has no effect on monsoon climate.

Westerlies in southern hemisphere are stronger and persistent than in northern hemisphere. Why? 1. Southern hemisphere has less landmass as compared to northern hemisphere. 2. Coriolis force is higher in southern hemisphere as compared to northern hemisphere. Which of the statements given above is/are correct?

The jet aircrafts fly very easily and smoothly in the lower stratosphere. What could be the appropriate explanation? 1. There are no clouds or water vapour in the lower stratosphere. 2. There are no vertical winds in the lower stratosphere. Which of the statements given above is/are correct in this context?