1. a. Photopsine
    b. Edward Jenner

2. a. Dysentery
        others are bacterial diseases.
    
    b. Oestrogen
       Others are the protein molecules which help blood clotting.

3. a. All the F₁ generations are Tall and red coloured flower plants.
    b. 
     c. Mendel's law of Independent  Assortment. When two or more pairs of characters combine, factors  for each character pair segregate and assort independently to pass onto the  next generation.

4. a. Finches which were similar in sound and nesting habits showed differences in food and habits.
   
    b. Changes in the environment  take variations in their structure.  The evolution of different species in a  given geographical area  start from a point to radiating other areas.  The original seed eating features changed into insectivorous and vegetarian finches due to the adaptive habits.  These changes give rise to the formation of new species.

5. A- At the end of the  axonite or synaptic knob.
    B- Synapse
    C- Dendrites of next neuron
        Synaptic  knob secretes a chemical substance known as acetyl choline which converts the electrical impulses into chemical impulses.

6. Parathormone secreted from parathyroid gland increases the calcium level in the blood.

a. Calcium ions are received  from the intestine, bones and nephrons to the blood and increases the    calcium level.  Parathormone helps this process.  Therefore  bones become brittle and  these excess calcium may be stored in the kidney to makes stones.

 b. If the parathormone production  decreases, calcium level in the blood also decreases, which affects the nervous system and  leads to muscle cramps.  That condition is known as tetany.

7.
    
8.
    
9. While passing urine, pathogens too are flushed out from the urinary bladder. Low intake of water, voluntary retention of urine will reduce the possibility of expelling bacteria that may be present in the urinary tract or urinary bladder are the reasons for UTI. The inner lining of the urinary bladder becomes inflammated due to infection.  Some times this infection leads to nephritis.

10. a. Heart, Eyes, Liver and Bonemarrow.
      b. When organ transplantation is done, the newly grafted organ is a foreign body as far as the body is concerned.  The body may react against the  grafted organ.

11. a. ECG
      b. Endoscopy
      c. Gene therapy
      d. X- ray

12. a. Theory of Inheritance of Acquired characters.
      b. Lamarck
13. a. Anti domine Vaccine or Anti- D
      b. If the Father is Rh+ve and Mother Rh -ve the new born will be Rh +Ve
After the  child birth the mother's body will produce antibodies against them.  Those antibodies will destroy the second child.  This condition is known as  erythroblastosis foetails.  Anti -D vaccine prevents  these antibodies.

14. A- Virus
      B- Bacteria

A- Virus
       When the  virus enter into the cell (host cell), they grow and multiply by under taking the control   of genetic  mechanism of the cell.  Therefore the virus infected cells are completely  destroyed.

B- Bacteria
   After entering into the body cell they grow and  multiply. When they multiply, certain toxic substances released into the  body disrupt the rhythm of cellular activities and destroy them.

15.
     
      a. Semicircular canals
      b. Cochlea
      c. Vestibule