CIE iGCSE Co-Ordinated Science B19.1 Habitat destruction Exam Style Questions Paper 3
Question
(a) The graph in Fig. 10.1 shows the area of land cleared by deforestation in one country between 2000 and 2010.
(i) Describe the pattern in the results shown in Fig. 10.1. Include data in your answer.
▶️Answer/Explanation
The graph shows that the area of land cleared by deforestation increased from 2000 to 2004, reaching a peak of approximately 27,000 hectares in 2004. After 2004, the area of land cleared decreased steadily, reaching around 7,000 hectares by 2009. The data indicates a significant reduction in deforestation after 2004.
(ii) Calculate the percentage decrease in the area of land cleared between 2008 and 2009.
▶️Answer/Explanation
To calculate the percentage decrease:
Area in 2008 = 12,000 hectares
Area in 2009 = 7,000 hectares
Decrease = 12,000 – 7,000 = 5,000 hectares
Percentage decrease = (5,000 / 12,000) × 100 = 41.67%
The percentage decrease in the area of land cleared between 2008 and 2009 is approximately 41.67%.
(b) Deforestation can cause a build-up of carbon dioxide in the atmosphere. Describe one way that humans directly increase the concentration of carbon dioxide in the atmosphere.
▶️Answer/Explanation
One way humans directly increase the concentration of carbon dioxide in the atmosphere is through the combustion of fossil fuels. When fossil fuels such as coal, oil, and natural gas are burned for energy, they release carbon dioxide as a byproduct, which contributes to the greenhouse effect and global warming.
(c) Many human activities create pollution which is harmful to the environment.
(i) The boxes on the left show some water pollutants. The boxes on the right show the sources of these pollutants.
Draw one line from each pollutant to its source.
▶️Answer/Explanation
Correct pairings:
- chemical waste → industries
- fertiliser → crop plant agriculture / farming
- rubbish (solid waste) → domestic / household waste
- untreated sewage → human and animal faeces
(ii) State one harmful effect of untreated sewage.
▶️Answer/Explanation
One harmful effect of untreated sewage is the spread of waterborne diseases such as cholera and dysentery. Untreated sewage contains harmful pathogens that can contaminate water sources, leading to outbreaks of disease in human populations.