Digestion is carried out by our digestive system by 
(a) Mechanical methods
 (b) Biological methods 
(c ) Biochemical methods 
Physiological methods

Match column I with column II and select the correct answer from the given codes. {:(Column I,Column II),(A. "The stage in which of physical treatment of sewage is done",(i)"Anaerobic digestion activated sludge and production of biogas"),(B."The stage in which biological treatment of sewage is done",(ii)"Activated sludge"),(C."Name of the sediment in primary treatment",(iii)"Aeration tanks"),(D."It is carried to aeration tanks from primary",(iv)"Primary effluent"),(E."Name of the sediment in secondary treatment",(v)"Primary sludge"),(F."site of flocs growth",(vi)"Secondary treatment"),(G."Function of sludge digester",(vii)"Primary treatment"):}

Mach column I with column II and select the correct answer from the given codes. {:(Column I,Column II),(A. "The stage in which of physical treatment of sewage is done",(i)"Anaerobic digestion activated sludge and production of biogas"),(B."The stage in which biological treatment of sewage is done",(ii)"Activated sludge"),(C."Name of the sediment in primary treatment",(iii)"Aeration tanks"),(D."It is carried to aeration tanks from primary",(iv)"Primary effluent"),(E."Name of the sediment in secondary treatment",(v)"Primary sludge"),(F."site of flocs growth",(vi)"Secondary treatment"),(G."Function of sludge digester",(vii)"Primary treatment"):}

Match column I with column II and select the correct answer from the given codes. {:(Column I,Column II),(A. "The stage in which of physical treatment of sewage is done",(i)"Anaerobic digestion activated sludge and production of biogas"),(B."The stage in which biological treatment of sewage is done",(ii)"Activated sludge"),(C."Name of the sediment in primary treatment",(iii)"Aeration tanks"),(D."It is carried to aeration tanks from primary",(iv)"Primary effluent"),(E."Name of the sediment in secondary treatment",(v)"Primary sludge"),(F."site of flocs growth",(vi)"Secondary treatment"),(G."Function of sludge digester",(vii)"Primary treatment"):}