🌍 Man and his Environment

1. Earth's natural resources are very important to Man as they provide Man with basic necessities, such as air, water, food and shelter, needed for survival.

2. Conservation of the environment is required to protect the Earth's natural resources.

3. The 3Rs — reducing, reusing and recycling are methods we can practise so that the Earth's natural resources will not be depleted too quickly.

4. Reducing involves using less natural resources whenever possible.

5. water can be conserved by reducing the amount of wastage used in households.

6. Reusing involves using the same resources again. By reusing plastic bottles, there will be fewer plastic bottles thrown away.

7. Recycling involves the conversion of waste materials into useful resources. By recycling worn-out tyres, new products such as the soles of shoes can be made, repurpose old or used items instead of throwing them away.

8. Less waste and rubbish will be produced by reducing the amount of resources used, reusing some resources instead of getting new ones and recycling some resources by converting them into new products.

9. Reforestation is another method to conserve the Earth's resources. It involves replanting trees in lands where the original trees had been removed.

1. Forests, minerals, marine life and fossil fuels are natural resources. These are depleting due to Man's rapid development.

2. Deforestation involves the excessive removal of trees in forests. It is often done to make way for agriculture and urbanisation.

3. Wood, obtained from trees, is a raw material used for constructing buildings, manufacturing paper and making furniture.

4. (a) By clearing forests, there will be fewer trees to take in carbon dioxide and give out oxygen into the air during photosynthesis.

(b) This may result in global warming as there will be too much carbon dioxide in the air.

5. (a) By clearing forests, many organisms will lose their habitats and die due to the lack of shelter and food.

(b) This may result in the extinction of some organisms.

6. By clearing forests, soil erosion may occur. There will be no tree roots to hold onto the soil, which results in the soil being washed away by water or blown away by wind.

7. By clearing forests, a large number of trees are lost, causing a disruption in the water cycle, whereby the amounts of water in the atmosphere and on land are affected.

8. Pollution refers to the introduction of harmful substances or pollutants into the environment, thus harming the environment.

9. Land pollution occurs when waste materials are not properly disposed of on land.

10. Water pollution occurs when waste materials or other harmful substances are introduced into water bodies.

11. Air pollution occurs when toxic gases or other harmful substances are released into the air / atmosphere.

12. Domestic wastes are wastes from households. These wastes cause pollution in water bodies and on land if not properly disposed of.

13. Non-biodegradable wastes, such as empty plastic bottles, are wastes that cannot be broken down by decomposers. These wastes are buried in landfills, increasing the amount of rubbish.

14. Polluted water bodies result in the deaths of many organisms living in the water.

15. Improper disposal of chemical wastes from factories / industries causes water pollution.

16. Oil from ships that spill into the sea / ocean causes water pollution.

17. Fertilisers and pesticides in agricultural areas might be washed into water bodies, causing water pollution.

18. Discharge of untreated sewage into water bodies causes water pollution. Sewage refers to waste water that contains laundry wastes, faeces and urine.

19. Smoke released from factories and vehicles into the atmosphere causes air pollution. An excessive amount of smoke in the air / atmosphere reduces visibility and causes respiratory problems.

20. Cigarettes also produce smoke that is harmful to us. It can cause diseases such as lung cancer and bronchitis.

21. Acidic gases released into the atmosphere results in the formation of acid rain, which can corrode buildings and statues. It can also kill aquatic organisms.

22. Chlorofluorocarbon (CFC) gases come from aerosols, refrigerators and air conditioners. They deplete the ozone layer in the upper atmosphere. This allows more harmful ultraviolet (UV) rays to enter the Earth's atmosphere.

23. The greenhouse effect is a process whereby greenhouse gases absorb and trap heat radiated from the Earth's surface, helping to keep the Earth warm.

24. Global warming refers to the rise of the Earth's average temperature.

25. Too much greenhouse gases such as carbon dioxide in the atmosphere will result in global warming as there will be more heat trapped on Earth.

26. Global warming will cause more icebergs to melt and sea levels to rise. This may eventually lead to floods in low-lying lands.

27. Fuels are burnt in power plants, factories and cars to provide energy.

28. Burning of fuels increases the amount of carbon dioxide in the air, leading to an increase in global temperature.

29. The use of electricity in everyday life needs to be reduced so that less fuels will be burnt in power stations.

30. (a) Deforestation removes a large number of trees. Less carbon dioxide will be absorbed from the air as there are fewer trees to carry out photosynthesis.

(b) As there is more carbon dioxide in the atmosphere to absorb and trap heat radiated by the Earth, global temperatures increase / rise.