Class 12th Biology 2018 Set1 Delhi Board Paper Solution
Following are the responses of different animals to various abiotic factors. Describe each one with the help of an example.
(i) Regulate (ii) Conform (iii) Migrate (iv) Suspend
(i) Regulate: Some animals as Birds and mammals can maintain their body temprature without influenced by the effect of external temp. Eg. Human can tolerate wide range of temp. without and change on its internal body temperature.
(ii) Conform: Conform are those that donnot maintain its body temp. their body temp. varies with change in external temperature. Eg. The cold blooded animals like reptile amphibian and pisces.
(iii) Migrate: Some of the animals during unfavorable condition start migrating to relief the abiotic stress and move to more hostile condition. Eg. Siberian crane migrate from Siberia to Bharatpur Bird Santuries during winter season.
(iv) Suspend: Organism during infavorable condition get inactive. Eg. Polar bear during winter season undergoes wnter sleep i.e. hibernation whereas frog, snail etc. undergoes summer sleep known as aestivation.
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:- Arrange the following terms in the correct developmental sequence:
- Q:- How is sex determined in human beings?
- Q:- Define population and community.
- Q:- How did Hershey and Chase differentiate between DNA and protein in their experiment while proving that DNA is the genetic material?
- Q:- What is meant by emasculation? When and why does a plant breeder employ this technique?
- Q:- List the various abiotic environmental factors.
- Q:-
Fill in the blanks:
(a) Humans reproduce __________. (asexually/sexually)
(b) Humans are__________. (oviparous/viviparous/ovoviviparous)
(c) Fertilization is __________ in humans. (external/internal)
(d) Male and female gametes are __________. (diploid/haploid)
(e) Zygote is __________. (diploid/haploid)
(f) The process of release of the ovum from a mature follicle is called__________.
(g) Ovulation is induced by a hormone called the __________.
(h) The fusion of male and female gametes is called _____________.
(i) Fertilisation takes place in _____________.
(j) Zygote divides to form _____________which is implanted in uterus.
(k) The structure which provides vascular connection between fetus and uterus is called ____________. - Q:- When a cross in made between tall plants with yellow seeds (Ttyy) and tall plant with green seed (Ttyy), what proportions of phenotype in the offspring could be expected to be (a) Tall and green. (b) Dwarf and green.
- Q:- Name important defence mechanisms in plants against herbivory.
- Q:- In the medium where E. coli was growing, lactose was added, which induced the lac operon. Then, why does lac operon shut down some time after addition of lactose in the medium?