Class 12th Biology 2012 Set3 Delhi Board Paper Solution

Question 15

Mention the importance of Lactic acid bacteria to humans other than setting milk into curd.
OR
How do methanagens help in producing biogas?

Answer
 Lactic acid bacteria play a very beneficial role in checking disease causing microbes.
 
OR
 
Methanogens such as Methanobacterium act on excreta of cattle and grow anaerobically, producing large amount of methane along with CO2 and H2. Methane is the main predominant gas of bio gas.