Class 12th Biology 2014 Set2 Delhi Board Paper Solution
Question 1
State the cause of accelerated eutrophication.
Answer
Accelerated eutrophication:
It is the ageing of a water body due to nutrient enrichment of its water. It can be natural or artificial. Eutrophication takes thousands of years, but due to human activities the process has been accelerated. So, it is called accelerated eutrophication.
Causes of accelerated eutrophication:
1) Release of nutrient-rich sewage and industrial effluents lead to the introduction of nutrients such as nitrogen and phosphorus.
2) Sewage and industrial effluents also lead to increase in temperature and BOD of the water body, causing increased biological activity, thereby leading to algal blooms.
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:- If one can induce parthenocarpy through the application of growth substances, which fruits would you select to induce parthenocarpy and why?
- Q:- What is the ecological principle behind the biological control method of managing with pest insects?
- Q:- Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?
- Q:- How is biodiversity important for ecosystem functioning?
- Q:- The species diversity of plants (22 per cent) is much less than that of animals (72 per cent). What could be the explanations to how animals achieved greater diversification?
- Q:- Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?
- Q:- List any three important characteristics of a population and explain
- Q:- Name the three important components of biodiversity.
- Q:- What would be the molar concentration of human DNA in a human cell? Consult your teacher.
- Q:-
What is meant by monosporic development of female gametophyte?