1. In a study conducted, the concentration of DDT found to increase in the successive trophic levels. The result of the study is shown below.
Name the phenomenon. How does DDT accumulation in birds affect their population? Explain. (4)
1. An article in the newspaper reports that ‘Refrigerants like Chlorofluorocarbons (CFCs) pose threat to the environment.’ How CFCs are harmful to the environment? (2)
1. A pond near to your home was with excessive algal bloom.
a. What are the possible reasons for this? (2)
b. What will be the level of BOD? (1)
c. Write any one case study for integrated waste water treatment. (1)
The temperature at New Delhi during April 2013 is 44.5o C. The earth’s temperature is regularly increasing.
a. What are the reasons for this? (2)
b. Write your suggestions to control this phenomenon. (2)
1. An aquatic ecosystem having luxurious growth of cyanobacteria (Algal bloom) leads to eutrophication.
(a) What kind of pollutants cause algal bloom to colonize the aquatic ecosystem ‘?
(b) What are the consequences of eutrophication? (Scores: 1 + 1 = 2)
2. During the past century, the temperature of the earth has increased by 0.6 °C, most of it during the last few decades. Rise in temperature causes deleterious changes in the environment, thus leading to increased melting of polar ice caps as well as other places like Himalayan snow caps. Suggest any two control measures that will reduce global warming. (Scores : 1 + 1 = 2)
1. Observe the diagram and answer the following:
a. Suggest the reasons for the presence of DDT in the water.
b. Fish eating birds of this area have higher DDT concentration in their body. Justify.
c. What will be the impact of DDT in the birds? (Scores: 1+1 + 2 =4)
United Nations Framework convention on climate change is an international treaty signed by 194 countries to cooperatively discuss global climatic change and its impact. As a science student,
a. What is global warming? (Score: 1)
b. Explain the reasons and give suggestions to control global warming. (Scores: 3)