Class 12th Biology 2016 Set2 Delhi Board Paper Solution
Question 9
List the events that lead to biogas production from waste water whose BOD has been reduced significantly.
Answer
After significant reduction of BOD, the effluent is passed into a settling tank where the floes are allowed to sediment to form activated sludge. This sludge is pumped into anaerobic sludge digesters where anaerobic bacteria digest the microbes of the sludge to release a mixture of gases such as methane, H2S and CO2. These gases form biogas which can be used as a source of energy.
Popular Questions of Class 12th biology
- Q:- What is spermatogenesis? Briefly describe the process of spermatogenesis.
- Q:- Why is reproduction essential for organisms? Answer
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals. - Q:- With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.
- Q:- What is DNA fingerprinting? Mention its application.
- Q:- What is oogenesis? Give a brief account of oogenesis.
- Q:- Describe the structure of a seminiferous tubule.
- Q:- What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.
- Q:- With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
- Q:- Explain the Law of Dominance using a monohybrid cross.
Recently Viewed Questions of Class 12th biology
- Q:- Explain what is meant by metastasis.
- Q:- Name the primary and secondary lymphoid organs.
- Q:- In which food would you find lactic acid bacteria? Mention some of their useful applications.
- Q:- Offspring formed due to sexual reproduction have better chances of survival. Why? Is this statement always true?
- Q:- List the various abiotic environmental factors.
- Q:- Define decomposition and describe the processes and products of decomposition.
- Q:- How is sex determined in human beings?
- Q:- What is the percentage of photosynthetically active radiation (PAR), in the incident solar radiation.
(a) 100%
(b) 50 %
(c) 1-5%
(d) 2-10% - Q:-
What is meant by monosporic development of female gametophyte?
- Q:- What is point mutation? Give one example.