Greenhouse effect is due to presence of
Ozone layer in the atmosphere.
Infra-red light reaching the earth
Moisture layer in the atmosphere
CO2 layer in the atmosphere
Which of the following activities is not a method to improve the environment?
Disposing of waste properly.
Reducing the use of fuels.
Producing less rubbish.
Using CFC products.
A, B, C, D and E are five busy cities in a country. Graph 1 shows the pollution of people in each of the cities. Graph 2 shows the level of air pollution in each city. Study both graphs and answer the following question.
Which one of the following can be concluded from the graphs shown?
The bigger the population of people living in a city, the higher the level of air pollution in that city.
The land is more polluted in city A than in city C.
City E contains the most pollutants in the air.
The air pollution in cities A and D are caused by burning forests.
Plankton are micro organisms that live in water bodies such as seas and ponds. They feed on other aquatic micro organisms that make food using sunlight. An oil spill has occurred on the sea near the south of Singapore.
Which one of the following graphs shows the population of plankton in the area affected by the oil spill?
Which one of the following is not used for disinfection of drinking water?
Chloromine
Chlorine
Ozone
Phenyl
Glass panel usually appear hazy because
Water vapour settles on the tiny dust particles.
It is the property of transparent substance
The glass is old
Of chemical reactions
Which of the following gases make up for most of the air?
Carbon dioxide
Hydrogen
Nitrogen
Oxygen
