- AHot air is lighter than cold air
- BHot air rises up
- CHot air expands
- ✓None of the above
Cyclones are called hurricanes in American continent and typhoons in Philippines and japan.

We know that increased wind speed is accompanied by reduced air pressure. Hence, the region inside the house, where there is no wind will be at a higher pressure.
Advanced Technology like satellites and radars, helps to issue cyclone warning in advance as they are continuously monitoring Earth from above and urgent messages can be broadcast to disaster-affected people via television and radio, these are the roles that advanced technology plays.
A Cyclone alert or Cyclone watch is issued $48$ hours in advance of any expected storm and a Cyclone warning is issued $24$ hrs in advance.
So cyclone warning is after cyclone alert.
Cyclones can be very destructive. Strong winds push water towards the shore even if the storm is hundreds of kilometres away. These are the first indications of an approaching cyclone.
High - speed winds and air pressure differences can cause cyclones. A large cyclone is a violently rotating mass of air in the atmosphere, $10$ to $15km$ high.
The diameter of the eye varies from $10$ to $30km.$
The centre of a cyclone is a calm area. It is called the eye of the storm. The diameter of the eye varies from $10$ to $30 km$. It is a region free of clouds and has light winds.