1. Which of the following is/are the example/ examples of chemical change? 
1. Crystallization of sodium chloride
2. Melting of ice

3. Souring of milk
 

Select the correct answer using the code given below.

2. Brominated flame retardants are used in many household products like mattresses and upholstery. Why is there some concern about their use? 
1. They are highly resistant to degradation in the environment.
2. They are able to accumulate in humans and animals.

Select the correct answer using the code given below.

3. With reference to two non-conventional energy sources called ‘coalbed methane’ and ‘shale gas’, consider the following statements : 
1. Coalbed methane is the pure methane gas extracted from coal seams, while shale gas is a mixture of propane and butane only that can be extracted from fine grained sedimentary rocks.
2. In India, abundant coalbed methane sources exist, but so far no shale gas sources have been found.

Which of the statements given above is/are correct?

4. Which one of the following is the process involved in photosynthesis?

5. Among the following organisms, which one does not belong to the class of other three?