How do Organisms Reproduce Class 10 Important Questions Science Chapter 8

Solved the very best collection of How do Organisms Reproduce Class 10 Science Important Questions and Answers Chapter 8 Pdf from the latest NCERT edition books, It will help you in scoring more marks in CBSE Exams.

How do Organisms Reproduce Class 10 Important Questions with Answers Science Chapter 8

How do Organisms Reproduce Class 10 Important Questions Very Short Answer Type

Question 1.
List two functions performed by the testis in human beings.   (Delhi 2015)
Answer:

  1. To produce sperms
  2. To produce male sex hormone/testosterone

Question 2.
Name the causative agent of the disease “Kala-azar” and its mode of asexual reproduction.   (Foreign 2015)
Answer:
Leishmania, Binary fission.

Question 3.
Name the life process of an organism that helps in the growth of its population.   (AI 2015)
Answer:
Reproduction.

Question 4.
Name the part of Bryophyllum where the buds are produced for vegetative propagation.   (Delhi 2016)
Answer:
Leaf (notches).

Question 5.
Name the method by which hydra reproduces. Is this method sexual or asexual ?   (Foreign 2016)
Answer:

  • Budding/Regeneration
  • Asexual reproduction

Question 6.
What happens when a mature spirogyra fiiament attains considerable length? (AI 2016)
Answer:
Its filament breaks up into smaller fragments or pieces, and each fragment grows into a new filament/individual.

How do Organisms Reproduce Class 10 Important Questions Short Answer Type

Question 1.
What is ‘reproduction’? Mention the importance of DNA copying in reproduction.   (CBSE 2008)
Answer:
Reproduction is the process by which the existing organisms produce their own kind. DNA copying during reproduction is important for the transfer of parental characters to the offspring.

Question 2.
List any two differences between pollination and fertilisation.   (CBSE 2008)
Answer:
Pollination

  1. Transfer of pollen grain from another to stigma of a flower.
  2. It is a physical process, no new substance is formed.
  3. Its types are self pollination and cross pollination.

Fertilisation:

  1. Fusion of pollen nucleus and ovule in the ovary.
  2. no new It is a chemical process in which a new structure called zvgote is formed.
  3. Its types are internal and external fertilisation.

Question 3.
Mention the information source of making proteins in the cell. What is the basic event in reproduction?  (CBSE 2008)
Answer:
Cellular DNA is the information source of making proteins in the cell.
The basic event in reproduction is copying of DNA so that the cells can further divide.

Question 4.
Name one sexually transmitted disease each caused due to bacterial infection and viral infection. How can these be prevented?   (AI 2008)
Answer:

  1. Bacterial infection: gonorrhoea, syphilis
  2. Viral infection: warts and HIV-AIDS
  3. Prevention: Use of condoms by male.

Question 5.
(a) In human body what is the role of
(i) Seminal vesicles
(ii) Prostrate glands.
(b) List two functions performed by testes in human beings.   (AI 2008)
Answer:
(a) Seminal vesicles: Produce a fluid which makes the transport of sperms easy.
Prostate glands: Produces a fluid which keeps sperms floating in it and provides nourishment.

(b) Two functions of testes:

  1. They secrete hormone: testosterone responsible for the male characteristics.
  2. It helps in the formation of sperms.

Question 6.
(a) Draw a diagram illustrating, fertilisation in a flowering plant and label it.
Pollen grain, male germ cell, female germ cell, stigma.
(b) Describe the process of fertilisation in plants.   (Foreign 2008)
Answer:
(a)
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 1

(b) Fertilisation in plants: It takes place after the pollination is done.

  • The pollen grain develops a tube called pollen tube which carries male germ cells to the ovary.
  • The male germ cell fuses with the female germ cell in the ovary and forms zygote.
  • The zygote further forms embryo.
  • The embryo develops a protective coating and forms seed.
  • The ovary forms a fruit with seed in it.

Question 7.
(a) Draw a diagram showing longitudinal section of a flower and label on it:
stigma, ovary, anther, filament.
(b) How is the process of pollination different from fertilisation? (Foreign 2008)
Answer:
(a)
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 2

(b)
Pollination:

  1. Transfer of pollen grain from anther to stigma of a flower.
  2. It is a physical process, no new substance is formed.
  3. Its types are self pollination and or cross pollination.

Fertilisation:

  1. Fusion of pollen nucleus and ovule in the ovary.
  2. It is a chemical process in which a new structure called zygote is formed.
  3. Its types are internal and external fertilisation.

Question 8.
Name the hormone the secretion of which is responsible for dramatic changes in appearance in girls when they approach 10-12 years of age.    (CBSE 2008)
Answer:
Oestrogen and Progesterone.

Question 9.
(a) Explain the terms:
(i) Implantation
(ii) Placenta
(b) What is the average duration of human pregnancy?   (CBSE 2009)
Answer:
(a) (i) Implantation: The zygote when fixes itself on the inner thick wall of uterus
for further development is called implantation.
(ii) Placenta: It is the special tissue in the form of a disc which is embedded in the uterus wall. It provides large surface area for glucose and oxygen to pass from mother to the embryo. The waste generated by the embryo also passes into the mother’s blood through this placenta

(b) It takes nine months for the human pregnancy.

Question 10.
What are sexually transmitted diseases? Name four such diseases. Which one of them damages the immune system of human body to complete?   (CBSE 2009)
Answer:
The diseases that spread due to sexual contact from infected person to a healthy person are called sexually transmitted diseases.

Four STDs:

  1. Gonorrhoea
  2. Syphilis
  3. Warts
  4. AIDS

AIDS: Acquired Immuno Deficiency Syndrome damages the immune system.

Question 11.
State one genetically different feature between sperms and eggs of humans. What is its consequence?  (CBSE 2012)
Answer:
Sperms consist of XY chromosomes and female eggs consists of XX chromosomes called as sex chromosomes. The egg cells can always contribute X chromosome while crossing whereas sperm can provide Y chromosome, hence the sex of the new born is determined by the contribution of male genetic information.

Question 12.
List two advantages of vegetative reproduction practised in case of an orange plant.   (CBSE 2012)
Answer:
Two advantages of practising vegetative reproduction in orange plants are:

  1. The oranges produced are similar in size and shape.
  2. Many oranges do not produce viable seeds and hence, vegetative method is a good alternative.

Question 13.
How does growing embryo get nutrition from the mother’s blood? (CBSE 2012)
Answer:
The embryo gets nutrition from the mother’s blood with the help of a special tissue called placenta. This is a disc which is embedded in the uterine wall and transfers glucose and oxygen from the mother to the embryo.

Question 14.
Define the term puberty. List two changes observed in girls at the time of puberty.   (CBSE 2012)
Answer:
The age when an individual attains a stage where its reproductive system becomes mature, starts functioning and the reproductive hormones are released is termed as puberty.
Two changes observed in girls at the time of puberty are:

  1. The breast size begin to increase,
  2. Menstruation starts.

Question 15.
What is meant by asexual reproduction? List its any two different forms.   (CBSE 2012)
Answer:
A sexual reproduction is the process of producing new organism from a single parent without the involvement of sex cells. Fission and fragmentation are two different forms of a sexual reproduction.

Question 16.
Name an organism which reproduces by spore formation. List three conditions favourable for spores to germinate and grow.   (CBSE 2012)
Answer:
Rhizopus reproduce by spore formation. Conditions favourable for spore formation are:
Darkness, dampness, cool place and presence of dead cells.

Question 17.
“DNA copies generated during reproduction will be similar but may not be identical to the original.” Justify this statement.   (CBSE 2012)
Answer:
DNA copies generated will be similar, but may not be identical to the original as some variations are so drastic that new DNA copy cannot work with the cellular apparatus it inherits. Such a newborn cell will simply die. Therefore, there could be many other variations in the DNA copies that would not lead to such a drastic outcome.

Thus, the surviving cells are similar but slightly different from each other. This tendency of variation during reproduction is the basis for evolution.

Question 18.
List two advantage of practising vegetative propagation in plants. Select two plants raised by this method from the list given below:
Banana, Gram, Pea, Rose, Tomato, Wheat.  (CBSE 2012)
Answer:
Advantages of vegetative propagation are:

  1. Plants raised by vegetative propagation can bear fruits and flowers earlier.
  2. Plants produced are genetically similar.
    Banana and Rose can be raised by vegetative method.

Question 19.
List the parts of human male reproductive system which contribute fluid to the semen. State two advantages semen offers to the sperms.   (CBSE 2012)
Answer:
Prostate glands and seminal vesicles add fluid in the vas deferens. This makes transportation of sperms easier and also provides nutrition to the sperms.

Question 20.
Name the two types of germ cells present in human beings. How do they structurally differ from each other? Give two differences.   (CBSE 2012)
Answer:
Two types of germ cells in human are sperm cell and egg cell.
Structurally both look very different sperm is very small with long tail for movement and egg is round or oval and quite big then a sperm cell.

Question 21.
List and explain in brief three methods of contraception.   (CBSE 2012)
Answer:
Three methods are surgical, physical and chemical.

  1. Surgical method: The vas deferens in male is tied/ blocked or the fallopian tube in female is tied/blocked.
  2. Physical method: The external contraceptives like condoms by males or by females is used.
  3. Chemical methods: The pills are taken orally to avoid the fusion of male sperm with the egg.

Question 22.
What is AIDS? Which microbe is responsible for AIDS infection? State one mode of transmission of this disease. Explain in brief one measure for the prevention of AIDS.   (CBSE 2012)
Answer:
AIDS is the Acquired Immune Deficiency Syndrome. It is caused by a virus called Human Immunodeficiency Virus. AIDS is transmitted by sexual contact with an infected person.
It can also be transmitted by the transfusion of fluid like blood or semen from infected person to a healthy person.

Prevention is the use of physical contraceptive like condoms can prevent the fluid from infected person to enter into the healthy person, the blood transfusion can also be monitored.

Question 23.
What is DNA copying? State its importance.   (Delhi 2015)
Answer:
A process where a DNA molecule produces two similar copies of itself in a reproducing cell.
Importance:

  1. It makes possible the transmission of characters from parents to the next generation.
  2. It causes variation in the population.

Question 24.
Explain budding in hydra with the help of labelled diagrams only.   (Delhi 2015)
Answer:
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 3

Question 25.
List any four methods of contraception’s used by humans. How does their use have a direct effect on the health and prosperity of a family?   (Delhi 2015)
Answer:
Four methods:

  1. Mechanical or barrier method OR Male or female condoms.
  2. Use of hormonal preparations OR Oral Pills/i-pill/Saheli.
  3. Use of loop or copper T OR IUCD.
  4. Surgical method OR tubectomy/vasectomy.

Effect on health and prosperity:

  1. Health of women is maintained,
  2. Parents can give more attention to children,
  3. More resources can be made available.

Question 26.
(i) Planaria, insects, octopus and vertebrates all have eyes. Can we group eyes of these animals together to establish a common evolutionary origin? Justify your answer.
(ii) “Birds have evolved from reptiles”. State evidence to prove the statement.   (Delhi 2015)
Answer:
(i) No, the structure of the eye in each of the organisms is different.
(ii) Fossils of certain dinosaurs, reptiles show imprints of feathers along with their bones but they could not fly presumably using the feathers for insulation. Later they developed, evolved and adapted feathers for flight, thus becoming the ancestors of present day birds.

Question 27.
Write the functions of the following in human female reproductive system:
Ovary, oviduct, uterus
How does the embryo get nourishment inside the mother’s body? Explain in brief.   (Delhi 2015)
Answer:
Functions:
Ovary:

  • Production of female hormone, oestrogen and progesterone.
  • Production of female gamete, egg, germ cell.

Oviduct:

  • Transfer of female gamete from the ovary.
  • Site of fertilization.

Uterus:

  • Implantation of Zygote, embryo.
  • Nourishment of developing embryo.

Placenta is a special disc like tissue embedded in the mother’s uterine wall and connected to the foetus, embryo. Placenta provides a large surface area for glucose and oxygen, nutrients to pass from the mother’s blood to the embryo or foetus.

Question 28.
How many pairs of chromosomes are present in human beings? Out of these how many are sex chromosomes? How many types of sex chromosomes are found in human beings?
“The sex of a newborn child is a matter of chance and none of the parents may be considered responsible for it”. Draw a flow chart showing determination of sex of a newborn to justify this statement.  (Delhi 2015)
Answer:
23 pairs of chromosomes.
One pair, two types.
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 4

Justification: Women produce only one type of ovum (cariying X chromosome) and males produce two types of sperms (carrying either X or Y chromosome) in equal proportions. So the sex of a child is a matter of chance depending upon the type of sperm fertilizing the ovum.

Question 29.
Write one main difference between asexual and sexual mode of reproduction. Which species is likely to have comparatively better chances of survival – the one reproducing asexually or the one reproducing sexually? Justify your answer.   (Foreign 2015)
Answer:
Asexual reproduction does not involve genetic fusion while sexual reproduction involves fusion of male and female gametes to form a zygote.
Species reproducing sexually have better chances of survival.

Reason: Sexual reproduction gives rise to more variations which are essential for evolution as well as survival of species under unfavourable conditions.

Question 30.
Explain the process of regeneration in Planaria. How is this process different from reproduction? (Foreign 2015)
Answer:
When Planaria is cut into many pieces, each piece grows into a complete organism; this regeneration process is carried out by specialized cell; which proliferate; develop and differentiate into various cell types and tissues. Regeneration is not same as reproduction as most of the organisms would not normally depend on being cut up to be able to reproduce.

Question 31.
What is placenta? Explain its function in humans.   (Foreign 2015)
Answer:
Placenta is a specialized tissue embedded in the uterine wall. It contains villi on the embryo’s side and blood spaces on the mother’s side.

Function: It helps in exchange of nutrients, gases and waste materials between the mother and embryo/foetus.

Question 32.
“It is a matter of chance whether a couple will have a male or a female child.” Justify this statement by drawing a flow chart.   (Foreign 2015)
Answer:
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 5

Justification: Women produce only one type of ovum (carrying X chromosome) and males produce two types of sperms (carrying either X or Y chromosome) in equal proportions. So the sex of a child is a matter of chance depending upon the type of sperm fertilizing the ovum.

Question 33.
List six specific characteristics of sexual reproduction.   (AI 2015)
Answer:
Characteristics:

  1. Two parents are involved.
  2. Two dissimilar gametes are formed, gamete formation involves meiosis.
  3. Variations are produced.
  4. Occurs in all the higher and some of the lower organisms.
  5. Fertilization/fusion of gametes leading to zygote formation.
  6. Slow.

Question 34.
What are chromosomes? Explain how in sexually reproducing organisms the number of chromosomes in the progeny is maintained.   (AI 2015)
Answer:
Chromosomes: Chromosomes are thread like structures which are made up of DNA and found in the nucleus.

The original number of chromosomes becomes half during gamete formation. Hence, when the gametes combine, the original number of chromosomes gets restored in the progeny, (same thing may be explained in the form of a flow chart).

Question 35.
List four points of significance of reproductive health in a society. Name any two areas related to reproductive health which have improved over the past 50 years in our country.   (AI 2015)
Answer:
Significance:

  • Prevents STDs,
  • Advantage of small family,
  • Less mortality among new borns,
  • Reduces the cases of maternal mortality.
    Areas which have improved – Family Planning, Decrease in STD cases.

Question 36.
How do organisms, whether reproduced asexually or sexually maintain a constant chromosome number through several generations? Explain with the help of suitable example.   (Delhi 2016)
Answer:

When organisms reproduce asexually, only mitotic divisions are involved and the chromosome number remains the same. During asexual reproduction the DNA (in the chromosomes) of the cells involved are copied and then equally divided among the two daughter cells formed. Thus, chromosome number remains unchanged.

In sexual reprodution, organisms produce gametes through a special type of division, meiosis-reductional division, in which the original number of chromosomes becomes half. These two gametes combine to form the zygote and the original number of chromosomes is restored. In sexual reproduction specialized cells/germ cells with only half the number of chromosomes are formed. When these germ cells from two individuals combine to form a new individual, the original chromosome number is restored.

Example: In humans, the parents father and mother each have 46 or 23 pairs of chromosomes. In the gametes – the sperm has half the number of chromosomes i.e., 23 and the egg also has 23 chromosomes, when the sperm and the egg fuse, the zygote has 46 or 23 pairs of chromosomes. Thus, the chromosome number remains constant.

Question 37.
Define reproduction. How does it help in providing stability to the population of species? (AI 2016)
Answer:
Reproduction: It is a (biological) process by which new individuals of the same species are produced by the existing organisms. Populations of organisms live in well defined places called niches in the ecosystem using their ability to reproduce. Reproduction involves DNA copying which is the source of information for making proteins thereby controlling body design.

These body designs allow the organism to use a particular niche for the stability of the population of a species. Minor variations may also lead to the stability of the species.

Question 38.
Name the parts A, B and C shown in the following diagram and state one function of each. (Delhi 2016)
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 6
Answer:
A. Anther – it produces pollen grains
B. Style – it provides the path through which the Pollen tube grows and reaches the ovary
C. Ovary – it contains ovules and each ovule has an egg cell/female gamete. It develops into fruit after fertilization.

Question 39.
Suggest three contraceptive methods to control the size of human population which is essential for the health and prosperity of a country. State the basic principle involved in each.   (Delhi 2016)
Answer:
Three methods of contraception –

  1. Barrier method or mechanical method/Condom/Diaphragm, to prevent the meeting of sperms and ova.
  2. Chemical method/Oral pills, changes the hormonal balance of the female partner so that the eggs are not released.
  3. Surgical method- to block the vasdeferens in males/vasectomy or the fallopian tube (oviduct) in females/tubectomy, to prevent the transfer of sperms or egg and hence no fertilization takes place.
  4. IUCDs/Loop or the copper-T placed in the uterus, to prevent pregnancy.

Question 40.
Explain the term “Regeneration” as used in relation to reproduction of organisms.
Describe briefly how regeneration is carried out in multicellular organisms like hydra.   (AI 2016)
Answer:
Regeneration – It is the ability of an organism to give rise to a new organism/ individual from their body parts.

Regeneration in hydra – When the body of hydra by any means is cut into number of pieces. Each piece contains specialized cells. These cells proliferate and make large number of cells. From this mass of cells different cells undergo changes to become various cell types and tissues finally developing into a new organism.

Question 41.
(a) List two reasons for the appearance of variations among the progeny formed by sexual reproduction.  (AI 2016)
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 7
(b) (i) Name the part marked ‘A in the diagram.
(ii) How does ‘A’ reaches part ‘B’?
(iii) State the importance of the part ‘C’.
(iv) What happens to the part marked ‘D’ after fertilisation is over?
Answer:
(a) (i) Involvement of two different individuals
(ii) Creation of new combination of variants

(b) (i) Pollen/pollen grain
(ii) By pollination/agents of pollination
(iii) It (pollen tube) helps male gamete to reach egg (ovule)
(iv) Converts into embryo.

How do Organisms Reproduce Class 10 Important Questions Long Answer Type

Question 1.
Illustrate the following with the help of a suitable diagrams:
(i) Regeneration in Planaria
(ii) Budding in Hydra   (AI 2008)
Answer:
(i) Regeneration in Planaria
Planaria: If it is divided into 3 parts a, b and c, each part grows as a new individual.
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 8

(ii) Budding in Hydra
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 9

Question 2.
Illustrate the following with the help of suitable diagram   (AI 2008)
(i) Spore formation in Rhizopus
(ii) Multiple fission in Plasmodium
Answer:
(i) Spore formation in Rhizopus
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 10

(ii) Multiple fission in Plasmodium
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 11

Question 3.
Illustrate the following with the help of suitable diagram.
(i) Binary fission in Amoeba
(ii) Leaf of Bryophyllum with buds
Answer:
(i) Binary fission in Amoeba
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 12

(ii) Bryophyllum leaf
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 13

Question 4.
(a) Identify A, B, C and D in the given diagram and write their names.
(b) What is pollination? Explain its significance.
(c) Explain the process of fertilisation in flowers. Name the parts of the flower that develop after fertilisation into
(i) seed, (ii) fruit   (Foreign 2008)
Answer:
(a) A – Stigma
B – Pollen tube
C – Ovary
D – Female germ cell / Egg cell

(b) Pollination – Transfer of pollen grains from anther to the stigma of a flower.
Significance of pollination – Process of pollination leads to fertilization as it brings the male and female gametes together for fusion.

(c) After a pollen falls on a suitable stigma, the pollen tube grows out of the pollen grain and travels through the style to reach the ovule in the ovary. Here the male germ cell (carried by the pollen tube) fuses with the female germ cell to form a zygote.
(i) Ovule
(ii) Ovary

Question 5.
Describe in brief the role of
(i) testis
(ii) seminal vesicle,
(iii) vas deferens,
(iv) ureter and
(v) prostate gland in human male reproductive system.   (CBSE 2012)
Answer:
(i) Testis: Testes are oval shaped primary reproductive organs in men. The function of testes is to produce sperms and male sex hormone testosterone. The scrotum provides optimal temperature for the formation of sperms.

(ii) Seminal vesicle: Seminal vesicles are a pair of thin walled muscular elongated sac which secrete fluid for nourishment of sperms.

(iii) Vas deferens: The sperms are carried by a long tube called vas deferens to organs called seminal vesicles where the sperms get nourishment and are stored.

(iv) Ureter: It is the tube that carries urine from kidney to the urinary bladder. In humans, there are two ureters, one attached to each kidney.

(v) Prostate glands: Prostate glands produce a fluid which is released in the urethra along with secretion of seminal vesicles for nourishment and transportation of sperms.

Question 6.
Draw a diagram of a human female reproductive system and label the part
(i) that produces egg
(ii) where fusion of egg and sperm take place
(iii) where zygote is implanted
What happens to human egg when it is not fertilised?   (CBSE 2012)
Answer:
How do Organisms Reproduce Class 10 Important Questions Science Chapter 8, 14
If the egg is not fertilised, the thick and nourishing lining of the uterus breaks and comes out through vagina as blood.

Question 7.
State in brief the changes that take place in a fertilised egg (zygote) till birth of the child in the human female reproductive system. What happens to the egg when it is not fertilised?   (CBSE 2012)
Answer:
The egg gets fertilised in the oviduct. The fertilised egg, the zygote gets implanted in the lining of the uterus and starts dividing. The uterus prepares itself every month to receive and nurture the growing embryo. The lining thickens and is richly supplied with blood to nourish the growing embryo.

The embryo gets nutrition from the mother’s blood with the help of a special tissue called placenta. The development of the child inside the mother’s body takes approximately nine months. On completion of 9 months, the child is born as a result of rhythmic contractions of the muscles in the uterus.

If the egg is not fertilised, the thick and nourishing lining of the uterus breaks and comes out through vagina as blood and mucus.

Question 8.
(a) Write the functions of the following parts in human female reproductive system:
(i) Ovary
(ii) Oviduct
(iii) Uterus
(b) Describe the structure and function of placenta.   (Delhi 2016)
Answer:
(a) (i) Ovary

  • Production of female hormone
  • Production of female

(ii) Oviduct

  • Transfer of female gamete from the ovary
  • Site of fertilization

(iii) Uterus

  • Implantation of the zygote
  • Nourishment of the developing embryo/placenta formation.

(b) Structure of Placenta: It is a disc like structure embedded in the uterine wall connected to the embryo. It has villi on the embryo’s side of the tissue and on the mother side, it has blood spaces, which surround the villi.

Function of Placenta: It provides a large surface area for nutrients/glucose and oxygen to pass from the mother’s side to the embryo and waste substances from the embryo’s side to mother’s blood.

Question 9.
What is vegetative propagation? List with brief explanation three advantages of practising this process for growing some types of plants. Select two plants from the following which are grown by this process:    (Foreign 2016)
Banana, Wheat, Mustard, Jasmine, Gram.
Answer:
Vegetative propagation is the development of a new plant from the vegetative parts – roots, stem and leaves of a plant.

Advantages:

  1. Such plants can, bear flowers and fruits earlier than those produced from seeds.
  2. Allows propagation of plants (banana, orange, etc) that have lost capacity to produce seeds.
  3. All plants produced are genetically similar to the parent plant and hence have all its characters.
    Jasmine, banana.

Question 10.
What is placenta? Describe its structure. State its functions in case of a pregnant human female.   (AI 2016)
Answer:
Placenta; A special tissue that helps human embryo in obtaining nutrition from mother’s blood.

Structure: This is a disc which is embedded in the uterine wall which contains villi on the embryo side of the tissue, and on the mother’s side are blood spaces which surround the villi.

Function: This provides a large surface area for glucose and oxygen to pass from the mother to the embryo, and the developing embryo will also generate waste substances which can be removed by transferring them into the mothers blood through the placenta.