Q4 of 19 Page 142

_________ is the chief component of natural gas.

Natural gas is primarily composed of methane. So its chief component is methane. Natural gas may also contain a small percentage of ethane, propane and higher hydrocarbons.

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2

The sedimented and floating materials are removed by this treatment process.

 3

Which is a non-renewable resource?

 1

The bar-graph indicates the prevalence / widespread attack of infectious diseases in two cities A and B. Observe it and answer the questions given below:

1. Dengue fever 2. Rat fever


3. Cholera 4. Chikungunya


a. What may be the reason for the disease in city A?


b. Which city needs a more effective system of waste-disposal and cleaning?


c. How can the disease be controlled in city A?


 2

The pie diagram represents a survey result of infectious diseases in a village during

2008 – 2009. Analyse it and answer the following:



i) Which diseases affect the majority of the population?


ii) How are these diseases transmitted?


iii) Mention any three measures that can control the other two diseases.