NCERT Exemplar solutions for Biology [English] Class 12 chapter 1 - Reproduction in Organisms [Latest edition]

Select the options that are true for both asexual and sexual reproduction from the options given below:

A few statements describing certain features of reproduction are given below:

1. Gametic fusion takes place
2. Transfer of genetic material takes place
3. Reduction division takes place
4. Progeny have some resemblance with parents

The term ‘clone’ cannot be applied to offspring formed by sexual reproduction because ______.

Asexual method of reproduction by binary fission is common to which of the following?

1. Some eukaryotes
2. All eukaryotes
3. Some prokaryotes
4. All prokaryotes

Choose the correct statements from the options below:

A few statements with regard to sexual reproduction are given below:

1. Sexual reproduction does not always require two individuals
2. Sexual reproduction generally involves gametic fusion
3. Meiosis never occurs during sexual reproduction
4. External fertilisation is a rule during sexual reproduction

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 ______.

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, ______.

Choose the correct statements.

Given below are a few statements related to external fertilization.

1. The male and female gametes are formed and released simultaneously
2. Only a few gametes are released into the medium
3. Water is the medium in a majority of organisms exhibiting external fertilization
4. Offspring formed as a result of external fertilization have better chance of survival than those formed inside an organism

Choose the statements that are true from the options below:

The statements given below describe certain features that are observed in the pistil of flowers.

1. Pistil may have many carpels
2. Each carpel may have more than one ovule
3. Each carpel has only one ovule
4. Pistil have only one carpel

Which of the following situations correctly describe the similarity between an angiosperm egg and a human egg?

1. Eggs of both are formed only once in a lifetime
2. Both the angiosperm egg and human egg are stationary
3. Both the angiosperm egg and human egg are mobile
4. Syngamy in both results in the formation of zygote

Choose the correct answer from the options given below:

Appearance of vegetative propagules from the nodes of plants such as sugarcane and ginger is mainly because ______.

Choose the correct answer from the options given below:

Which of the following statements, support the view that elaborate sexual reproductive process appeared much later in the organic evolution.

1. Lower groups of organisms have simpler body design
2. Asexual reproduction is common in lower groups
3. Asexual reproduction is common in higher groups of organisms
4. The high incidence of sexual reproduction in angiosperms and vertebrates

Offspring formed by sexual reproduction exhibit more variation than those formed by Asexual reproduction because ______.

Choose the correct statement from amongst the following.

There is no natural death in single celled organisms like Amoeba and bacteria because ______.

There are various types of reproduction. The type of reproduction adopted by an organism depends on ______.

Identify the incorrect statement.

Which of the following is a post-fertilization event in flowering plants?

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 ______.

Mention two inherent characteristics of Amoeba and yeast that enable them to reproduce asexually.

Why do we refer to offspring formed by asexual method of reproduction as clones?

Although potato tuber is an underground plant part, it is considered as a stem. Give two reasons.

Between an annual and a perennial plant, which one has a shorter juvenile phase? Give one reason.

Rearrange the following events of sexual reproduction in the sequence they occur in a flowering plant:

Embryogenesis, Fertilisation, Gametogenesis, Pollination.

The probability of fruit set in a self-pollinated bisexual flower of a plant is far greater than a dioecious plant. Explain.

Is the presence of large number of chromosomes in an organism a hindrance to sexual reproduction? Justify your answer by giving suitable reasons.

Is there a relationship between the size of an organism and its life span? Give two examples in support of your answer.

In the figure given below the plant bears two different types of flowers marked ‘A’ and ‘B’. Identify the types of flowers and state the type of pollination that will occur in them.

Give reasons as to why cell division cannot be a type of reproduction in multicellular organisms.

In the figure given below, mark the ovule and pericarp.

Why do gametes produced in large numbers in organisms exhibit external fertilisation?

Which of the followings are monoecious and dioecious organisms?

Match the organisms given in Column-’A’ with the vegetative propagules given in column ‘B’.

What do the following parts of a flower develop into after fertilisation?

In haploid organisms that undergo sexual reproduction, name the stage in the life cycle when meiosis occurs. Give reasons for your answer.

The number of taxa exhibiting asexual reproduction is drastically reduced in higher plants (angiosperms) and higher animals (vertebrates) as compared with lower groups of plants and animals. Analyse the possible reasons for this situation.

Honeybees produce their young ones only by sexual reproduction. Inspite of this, in a colony of bees we find both haploid and diploid individuals. Name the haploid and diploid individuals in the colony and analyse the reasons behind their formation.

With which type of reproduction do we associate the reduction division? Analyse the reasons for it.

Is it possible to consider vegetative propagation observed in certain plants like Bryophyllum, water hyacinth, ginger etc., as a type of asexual reproduction? Give two/three reasons.

'Fertilisation is not an obligatory event for fruit production in certains plants'. Explain the statement.

In a developing embryo, analyse the consequences if cell divisions are not followed by cell differentiation.

List the changes observed in an angiosperm flower subsequent to pollination and fertilisation.

Suggest a possible explanation why the seeds in a pea pod are arranged in a row, whereas those in tomato are scattered in the juicy pulp.

Draw the sketches of a zoospore and a conidium. Mention two dissimilarities between them and atleast one feature common to both structures.

Justify the statement ‘Vegetative reproduction is also a type of asexual reproduction’.

Enumerate the differences between asexual and sexual reproduction. Describe the types of asexual reproduction exhibited by unicellular organisms.

Do all the gametes formed from a parent organism have the same genetic composition (identical DNA copies of the parental genome)? Analyse the situation with the background of gametogenesis and provide or give suitable explanation.

Although sexual reproduction is a long drawn, energy-intensive complex form of reproduction, many groups of organisms in Kingdom Animalia and Plantae prefer this mode of reproduction. Give atleast three reasons for this.

Differentiate between oestrus and menstrual cycles. Cite an example for each type.

Differentiate between ovipary and vivipary. Cite an example for each type.

Rose plants produce large, attractive bisexual flowers but they seldom produce fruits. On the other hand a tomato plant produces plenty of fruits though they have small flowers. Analyse the reasons for failure of fruit formation in rose.

Both these plants - rose and tomato - both selected by human beings for different characteristics, the rose for its flower and tomato for its fruit. Roses, being vegetatively propagated do not need to produce seeds.