Class 12th Biology 2013 Set3 Delhi Board Paper Solution
Question 13
Explain the steps that ensure cross pollination in an autogamous flower.
Answer
Following steps can ensure cross pollination in autogamous flowers
(i) Pollen grain and stigma receptivity should not be synchronized.
(ii) Anther and stigma are placed at different positions so that pollen cannot come in contact with stigma of the same flower.
(iii) Self incompatibility also prevents inbreeding.
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:- Describe the structure of a seminiferous tubule.
- Q:- What is oogenesis? Give a brief account of oogenesis.
- 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:- 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:- What are sacred groves? What is their role in conservation?
- Q:- How is biodiversity important for ecosystem functioning?
- Q:- Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?
- Q:- What is the significance of the slope of regression in a species − area relationship?
- Q:- What is DNA fingerprinting? Mention its application.
- Q:- Define decomposition and describe the processes and products of decomposition.
- Q:- Differentiate between gametogenesis from embryogenesis.
- Q:- Fill in the blanks.
(a) Plants are called as_________ because they fix carbon dioxide.
(b) In an ecosystem dominated by trees, the pyramid (of numbers) is _________ type.
(c) In aquatic ecosystems, the limiting factor for the productivity is _________.
(d) Common detritivores in our ecosystem are_________.
(e) The major reservoir of carbon on earth is_________. - Q:-
Secondary producers are
(a) Herbivores
(b) Producers
(c) Carnivores
(d) None of the above