Directions : Read the given passage and answer the questions that follow by Selecting the most appropriate option.
Scientists are extremely concerned about the changes taking place in our climate. The changes are said to be alarmingly rapid and the result of human activity whereas in the past it had been natural and much slower . The major problem is that the planet appears to be warming up (global warming) This is occurring at a rate unprecedented in the last 10,000 years. The implications are very serious, Rising temperatures could give rise to extremely high increase in the incidence of floods and droughts, having effect on agriculture.
It is thought that this unusual warming of the Earth has been caused by greenhouse gases, such as carbon dioxide, being emitted into the atmosphere by car engines and modern industrial processes. Such gases not only add to the pollution of the atmosphere, but trap the heat of the sun leading to the warming up of the planet.
It has been suggested that industrialized countries would try to reduce the volume of greenhouse gas emissions and plant more trees to create ‘ sinks ’ to absorb greenhouse gases.

Greenhouse gases refer to

1. A
   emission of gases by the cars alone.
2. B
   emission of gases by the industries alone.
3. C
   trapping of heat of the sun by the earth increasing temperature alone.
4. D
   Carbon dioxide being produced from any source.