As a result of global warming the frequency and severety of which of the following are increasing due to global warming?

1. A

   Cyclones only

   Warmer oceans and a more energetic atmosphere are linked to changes in tropical cyclone behaviour. Frequency and intensity of such storms are discussed as climate-change impacts, but cyclones are only one class of the listed phenomena. This option is incomplete, so it is not the key.

2. B

   Storms only

   Storms in a broader sense, including extra-tropical and convective storms, can become more severe as the atmosphere holds more moisture. The question also names cyclones and hurricanes. Storms alone do not cover the full list. This option is not the key.

3. C

   Hurricanes only

   Hurricanes are the Atlantic and eastern-Pacific name for intense tropical cyclones. Their intensity and rainfall are widely linked to warming seas. The option says hurricanes only, which excludes the other named types. This option is therefore wrong as a complete answer.

4. D

   All of the above

   Cyclones, storms and hurricanes are related families of violent weather. Global warming raises sea-surface heat and atmospheric moisture, which can increase the frequency and severity of such events as a group. The paper therefore keys all of the above. This option is the official key.

Summary. Official key is (d) All of the above. The stem asks which phenomena are becoming more frequent and severe with global warming and lists cyclones, storms and hurricanes. Those names overlap regionally but all belong to extreme-weather systems fed by warmer oceans and a wetter atmosphere. Picking any one type alone leaves the others out. Only (d) matches the full list as stored.