8.2 3.1.3 environment  (Page 7/8)

3.1.Name the independent variable in this investigation.(1)

3.2.Name the dependent variable in this investigation.(1)

3.3.Name TWO ways in which the investigation could be improved to obtain accurate and valid results.(2)

3.4.Describe the relationship between pH and the number of germinating seeds. (2)

3.5.Suggest THREE strategies that the government can use to help reduce the formation of acid rain. (3)

QUESTION 4

The graph below shows the effect of biocontrol on an invasive alien plant population.

Graph showing the effect of biocontrol on an invasive alien plant population.

4.1.Explain what is meant by the term ‘biocontrol’.(1)

4.2.Give two reasons that you can see from the graph to support the fact that biocontrol has been successful in controlling the alien plant population. (2)

4.3.Why is host specificity so important when introducing a biocontrol agent?(2)

Read the following text and answer the questions that follow:

QUESTION 5:

GLOBAL BURDEN OF DISEASE DUE TO INDOOR AIR POLLUTION

In the year 2000, indoor air pollution from solid fuel use was responsible for more than 1,6 million annual deaths. Smoke and gases that come from the burningof fossil fuels, such as coal, charcoal and wood, to heat homes and to cook contributes to indoor pollution.

Dependence on burning fossil fuels to meet basic energy needs is one of the underlying causes of asthma, bronchitis, pneumnia and other respiratoryillnesses among children.

Adapted from: http://www.who.int/indoorair/health_impacts/burden_global/enprint.html

5.1 Name THREE illnesses that are thought to be made worse by exposure to indoor pollution.(3)

5.2 Why do you think indoor pollution causes so many medical problems?(2)

Suggest TWO ways in which communities can try to decrease the negative effects of indoor pollution.(2)

Studies show that the average South African has a “carbon footprint” that is higher than the world average because most of our electricity isgenerated from burning coal.

5.3 State THREE ways to solve this problem.(3)

Question 6

(NSC Additional Exemplar 2008 Life Science Paper 2 Question 1)

Study the table below showing the amount of medical waste produced by three provinces over a number of years

6.1Which province has shown the most rapid increase in the amount of medical waste produced?(1)

6.2What was the percentage increase of medical waste produced by the province named in QUESTION 2.1 over the period 1995 to 2003? Show ALL workings. (3)

6.3Give TWO negative effects of dumping medical waste.(2)

Question 7

The graph below shows the effect of different amounts of sewage discharged into a river, on the amount of dissolved oxygen in the water. Study the graph andanswer the questions that follow.

7.1.Why does the sewage discharge cause oxygen levels to decrease?(2)

7.2.Why does the minimum amount of oxygen occur some distance downstream of the point of sewage discharge?(2)