TEST PAPER 8 - UNIT 8 - 25 MARKS

There are 14 questions in all and time limit is 45 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 4]

1. The number of genes in human being is about...
   
   
   
   1. 23
   2. 46
   3. 1,000 to 2,000
   4. 30,000 to 40,000
      
   
   
2. ______ gave Germplasm theory.
   
   
   
   1. Lamarck
   2. Weismann
   3. Darwin
   4. Hugo De Vries
      
   
   
3. Biological oxygen demand of ______ is the least.
   
   
   
   1. sewage
   2. sea water
   3. pure water
   4. polluted water
      
   
   
4. ______ is the first step of sewage treatment.
   
   
   
   1. Precipitation
   2. Chlorination
   3. Sedimentation
   4. Aeration
      
   
   

   SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 4]

   
   
5. Define : Heredity.
6. Mutation is one of the reasons of variation. True or false ?
7. Mention the major reason for environmental problems.
8. What is biomagnification ?
   

   SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 6]

   
   
9. Explain : Analogous organs giving example.  OR  Mention components of nucleotides.
10. Explain : Acid rain.
11. Describe oxidation pond method.
    

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 6]

    
    
12. Explain Mendel's concept of heredity.
13. Describe harmful effects of water pollution.  OR   Describe the interrelationship among population, environment and development.
    

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 5]

    
    
14. Describe Watson-Crick model for the structure of DNA with diagram.