This page lists the current chapter structure for
Class 12 Biology.
231
Active Questions
13
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Class 12 Biology Quick Practice
Try real questions from active chapters in this subject.
Question 1 of 8
Choose the correct statement from amongst the following:
Correct answer: B
Dioecious organisms have male and female reproductive structures on separate individuals. Such separation occurs in both plant and animal groups.
Question 2 of 8
The male gametes of rice plant have 12 chromosomes in their nucleus. The chromosome number in the female gamete, zygote and the cells of the seedling will be respectively
Correct answer: B
Gametes are haploid, so the female gamete also has 12 chromosomes. Fertilisation restores the diploid number to 24 in the zygote, and seedling cells remain diploid.
Question 3 of 8
There is no natural death in single celled organisms like Amoeba and bacteria because:
Correct answer: B
During binary fission in unicellular organisms, the parental cell divides into daughter cells. The parental body is distributed into offspring rather than persisting as a dead body.
Question 4 of 8
A multicellular, filamentous alga exhibits a type of sexual life cycle in which the meiotic division occurs after the formation of zygote. The adult filament of this alga has
Correct answer: A
When meiosis occurs after zygote formation, the life cycle is haplontic. The dominant adult filament is haploid, and its gametangia are also haploid.
Question 5 of 8
The term ‘clone’ cannot be applied to offspring formed by sexual reproduction because:
Correct answer: D
Sexual reproduction combines genetic material from gametes and produces recombination. The offspring are not exact genetic copies of a single parent, so they are not clones.
Question 6 of 8
The number of chromosomes in the shoot tip cells of a maize plant is 20. The number of chromosomes in the microspore mother cells of the same plant shall be :
Correct answer: D
Shoot tip cells are diploid somatic cells. Microspore mother cells are also diploid before meiosis, so they have the same chromosome number, 20.
Question 7 of 8
Identify the incorrect statement.
Correct answer: C
Zoospores are motile asexual reproductive structures. Calling them sexual reproductive structures is therefore the incorrect statement.
Question 8 of 8
Offspring formed by sexual reproduction exhibit more variations than those formed by asexual reproduction because:
Correct answer: C
Sexual reproduction brings together genetically different gametes and allows recombination. This creates more variation than asexual reproduction.
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