Subject

Biology

Class

ICSE Class 12

Pre Boards

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Sample Papers

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 Multiple Choice QuestionsShort Answer Type

31. Define cardiac output. Describe the mechanism regulating the heart beat.
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32. Describe the events that take place from the time of entry of the human sperm into the ovum till fertilization is complete. 
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33.

Explain the following :

(i) Grafting
(ii) Vital capacity
(iii) Ureotelism
(iv) Epigeal germination.

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34. Draw a labelled diagram of the transverse section of the cochlea of the human ear.
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35. What is seed dormancy ? How can it be broken artificially ? 
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36. Give an account of the evidence which shows the common ancestry of man and apes. 


Following evidences support the idea of common ancestry of man and apes :

1. Evidences from Anatomy :

(1) Morphological similarities : Man and apes show many morphological similarities such as tailless body, bipedal locomotion, erect posture, dental formula, structure of teeth.

(2) Vestigial organs : Vestigial organs found in man are present in apes also, either as functional organs or as vestigial organs.

2. Physiological Evidences :

1. There are similarities in the blood proteins, leucocytes and blood groups of man and apes.

2. Menstrual cycle in human female is 28 days while it is 28-30 days in chimpanzee and 30-35 days in gorilla.

3. Gestation period is 270-290 days in human beings, 265-280 days in gorilla and 210-252 days in chimpanzee.

3. Embryological Evidences :

1. The eggs and sperms of man and apes are indistinguishable.

2. Six week embryo of man has several pairs of mammae like those of other anthropoids.

3. The human embryo is covered with hair.

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37. Describe the Oparin-Haldane theory of the origin of life.
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38. What are vestigial organs ? 
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39. Explain hybridization. Describe the various techniques of hybridization in plants. 
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40. Enumerate any three causes of mental illness ?
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