Class 12th Biology 2017 Set1 Outside Delhi Board Paper Solution
Question 21
‘‘Organisms may be conformers or regulators.’’ Explain this statement and give one example of each.
Answer
"Regulators" : The organism maintain homeostasis by physiological and behavioural means. All birds and mammals and few lower vertebrates and invertebrates species maintain homeostasis by thermoregulation and osmoregulation.
In mammals during summer sweating occurs profusely and the evaporation brings down temperature of the body.
For eg : - Birds & Mammals.
"Conformers" : - Majority (99%) of animals and allmost all plants cannot maintain a constant internal environment. Their body temperature is not constant and changes with the elimate. They are simply conformers. Eg: Aquatic organisms,Fishes, Frogs etc.
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:- Name some traditional Indian foods made of wheat, rice and Bengal gram (or their products) which involve use of microbes.
- Q:- The following are some well-known abbreviations, which have been used in this chapter. Expand each one to its full form:
(a) MALT
(b) CMI
(c) AIDS
(d) NACO
(e) HIV - Q:- What is spermatogenesis? Briefly describe the process of spermatogenesis.
- Q:- What would be the molar concentration of human DNA in a human cell? Consult your teacher.
- Q:- What is vegetative propagation? Give two suitable examples.
- Q:- Distinguish between the following:
(a) Hibernation and Aestivation
(b) Ectotherms and Endotherms - Q:- Differentiate between:
(a) Hypocotyl and epicotyl
(b) Coleoptile and coleorrhiza
(c) Integument and testa
(d) Perisperm and pericarp - Q:- Name important defence mechanisms in plants against herbivory.
- 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:- What are chasmogamous flowers? Can cross-pollination occur in cleistogamous flowers? Give reasons for your answer.