Chapter 15 : REPRODUCTION IN ORGANISMS

1. What is reproduction? What is the aim (purpose) of reproduction?
   ANS
   
   • Reproduction is the process by which new organisms of the same species are produced by existing living organisms.
   • The aim of reproduction is the continuation of life on earth. It ensures survival of the existing species of organisms and formation of new species from existing ones by the process of evolution.
2. How do organisms create exact copies of themselves?
   ANS
   
   • Organisms of the same species have similar characteristics as regards body design and body function.
   • In the nucleus of the cells of an organism, the information controlling the common characteristics of the species is stored in DNA.
   • This information leads to the synthesis of proteins controlling the characteristics of the species.
   • During reproduction, duplication of DNA takes place and the information is exactly copied. This leads to the formation of new cells with similar characteristics.
   • If the information is changed due to some reason, the characteristics transferred to the progeny change and the body design changes in the progeny.
   • If these changes are compatible, then the cells survive and a progeny with differing characteristics comes into existence.
   • This is called variation and is the essence of evolutionary process.
3. Describe the importance of variation.
   ANS
   
   • Reproduction gives stability of populations of species in an ecosystem by the maintenance of overall body features.
   • This is achieved by consistency of DNA copying during reproduction.
   • However, the niches (ecosystems) keep on changing because the factors affecting the change are not controlled by the organisms.
   • Alteration in temperature, humidity, water level and phenomena like meteorite hits are examples of factors affecting the change.
   • Suppose the population of reproducing organisms is suited to a particular niche and if there is a drastic change in the niche, the population may be wiped out.
   • But if there were some variations present in a few individuals of this population, there would be some chance for them to survive.
   • For example, if there was a population of bacteria living in water with moderate temperature and if the water temperatures were to rise due to global warming, many bacteria would die but a few temperature resistant bacteria would survive and grow further.
   • Thus, variation is useful for the survival of the species.
4. What is the basic difference between asexual reproduction and sexual reproduction?
   ANS
   The basic difference between asexual reproduction and sexual reproduction is that only one parent is required for asexual reproduction, i.e. there is no distinction like male and female whereas sexual reproduction requires two parents, one male and one female.
5. Describe different methods (types) of asexual reproduction.
   ANS
   
   • Fission:
     • This is the simplest method of asexual reproduction in which a unicellular organism (like protozoa, bacteria) divides to form two new organisms.
     • There are two types of fission: (i) Binary fission (ii) Multiple fission.
     • Binary Fission:In binary fission, the nucleus lengthens and divides into teo parts. Then the cytoplasm divides into two parts, one part around each nucleus. This results into two daughter cells which then grow as individual organisms.
       Example: Amoeba, Paramoecium.
       
       
     • Multiple Fission: Under certain circumstances, the nucleus of the cell divides several times within the cell forming many nuclei. Particularly when a unicellular organism forms cyst around the cell during unfavourable conditions, the nucleus divides several times within the cyst forming many smaller daughter nuclei. Each nucleus is then surrounded by a small amount of cytoplasm and a thin membrane. When favourable conditions arrive, the cyst breaks and all those daughter cells are released.Each cell then forms a new organism.
       Example: Plasmodium, Amoeba.
       
       
   • Fragmentation: Fragmentation is the breaking up of the body of a multicellular organism into two or more pieces. On maturing each piece grows to form a completely new organism.
     Example: Spirogyra.
     
     
   • Regeneration:
     • Regeneration is the ability of an organism to reproduce the lost parts of its body.
     • When some body part of an organism breaks suddenly, a new part similar to the lost (broken) part is created at the point of breaking after some time.
     • All broken parts thus develop into completely new organisms.
       
       
   • Budding:
     • A small part of the body of the parent organism grows out as a bud.
     • On maturing the bud gets detached from the parent and becomes a new organism.
       Example: Hydra, Yeast
       
       
   • Spore Formation:
     • Spores are microscopic reproductive units of plants.
     • Spores are covered by a protective coat.
     • When the spore coat bursts, the spores spread into air.
     • These air-borne spores germinate to produce new plants under favourable conditions if they settle on food.
       Example: Rhizopus, Mucor
       
       
6. Write a brief note on Vegetative propagation.
   ANS
   
   • Vegetative propagation is an asexual method of reproduction occurring only in plants.
   • New plants are obtained from old plants using their parts like roots, stem or leaves. Thus, reproductive organs are not involved in this method.
   • It involves development and growth of dormant buds present in the parts of old plants.
   • These dormant buds grow into a new plant under suitable conditions of temperature and moisture.
   • For example, buds present on bryophyllum leaves develop into a new plant.
   • There are several buds on a potato tuber. When these buds are planted in the ground, a new plant develops.
     
     
     
     
     
7. Describe various methods of Artificial Propagation.
   ANS
   
   • Artificial propagation involves development of a new plant from an old plant using artificial method.
   • The commonly used methods of artificial propagation are: (i) Cutting (ii) Layering (iii) Grafting.
   • CUTTING: A cutting of stem or shoot or leaf having buds on it is taken and its lower part is buried in the moist soil. After some days the cutting develops roots and grows into a similar plant. The advantage of this method is that many new plants can be grown from one plant in short time without seeds.
     Example: Rose, Bougainvillae.
     
     
   • Layering: In this method a part of stem is pulled towards the ground and covered by the soil. The covered part develops roots after some time and behaves as an independent plant. It is then separated from the parent plant and grows into a mature plant.
     Example: Lemon, Bougainvillae, Crysenthemum.
     
     
   • Grafting:
     • In this method two parts (stems) of different plants are joined together in such a way that they unite to grow as one plant.
     • The portion of the plant having roots is called 'stock'.
     • The portion of the plant without roots is called 'scion'.
     • By this method desirable characteristics of different plants can be combined.
     • This method is useful for plants whose seeds have long dormancy period and poor germination capacity.
     • Example: On the stock of lemon, a scion of lemon or orange can be grafted.
       
       
8. What is sexual reproduction? Describe its importance.
   ANS
   
   • Sexual reproduction is the process in which a male gamete and a female gamete unite to produce a zygote which develops into a new organism after some time.
   • IMPORTANCE:
     • Sexual reproduction introduces genetic variations which lead to a greater variety in offspring.
     • Genetic variations bring diversity of characters.
     • It gives different species of plants and animals to adapt to the changing environment. Organisms which adapt quickly to these changes survive and reproduce sexually.
     • Sexual reproduction plays an important role in the origin of new species through evolution.
9. Describe sexual reproduction in flowering plants.
   ANS
   
   • Flower is the reproductive part in higher plants.
   • The reproductive organs are located within the flower.
   • If the same flower contains both the male and female reproductive organs, the plant is known as bisexual.
   • The function of the flower is to produce male and female gametes and to ensure fertilization.
   • The male organ is called stamen and it produces male gametes.
   • The female organ is called carpel and it produces female gametes.
   • Female gametes are called ova or egg cells and they are present in ovules.
   • Male gametes are present in pollen grains and they fertilize the egg cells in ovules.
   • The fertilized egg cell develops within ovule which produces embryo and then entire ovule is converted into a seed.
   • Seeds germinate to produce new plants under favourable conditions.
     
     
10. Write a brief note on puberty.
    ANS
    
    • Puberty is the stage in the life of a human being when the reproductive organs show gradual changes in structure and they become functional.
    • A boy attains puberty at the age of 13-14 years whereas a girl attains puberty at the age of 12 years.
    • During puberty, testes in male start producing male gametes (sperms) and the sex hormone testosterone.
    • Similarly, ovaries in female start producing female gametes (ova) and sex hormones estrogen and progesterone.
    • During puberty hair grow in armpits and around genital organs between the thighs. This is common to both boys and girls.
    • In addition, in boys the body becomes more muscular, the voice deepens and shoulders and chest broaden. The penis grows and becomes capable to be erect.
    • In girls, the breasts show development and the reproductive system changes. These changes are necessary to accommodate developing child within mother's body and to breast-feed the child after birth.
    • This stage between childhood and adulthood is called 'adolescence'.
11. Describe reproductive system in human male with diagram.
    ANS
    
    • A pair of testes is the main reproductive organ in human male.
    • Testes produce male gametes,i.e., sperms and the male sex hormone testosterone.
    • Epididymis, vas deferens and penis are the accessory reproductive organs which facilitate the transfer of gametes to the site of fertilization.
    • Seminal vesicle and prostate gland are accessory reproductive glands.
    • The two oval shaped testes lie in a muscular sac called scrotum outside the abdominal cavity.
    • The temperature in the scrotum is 2 to 3° C lower than the body temperature. This temperature is suitable for the formation of sperms.
    • The sperms produced in testes are transported to penis through epididymis and vas deferens.
    • Vas deferens connects to the urinary duct coming from urinary bladder.
    • Seminal vesicle and prostate gland secrete fluids which mix with sperms and increase their mobility.
    • Urethra transfers sperms to penis and sperms pass into vagina through genital pore during mating.
      
      
12. Describe reproductive system in human female with diagram.
    ANS
    
    • Female reproductive system in humans is more complicated than that in male as fertilization and development of embryo takes place in it.
    • It consists of ovaries, oviduct, uterus and vagina.
    • Two ovaries are oval in shape and lie within the abdominal cavity.
    • Ovaries produce ova or eggs and secrete female sex hormones estrogen and progesterone.
    • There are two fallopian tubes (oviducts) which are funnel shaped and which receive the mature ova released by the ovary.
    • Oviducts carry the ova from ovary to the uterus, if it is fertilized by a sperm.
    • Uterus is a muscular bag where the fertilized egg further develops into embryo.
    • The lower tip of the uterus is called cervix.
    • The ovaries contain thousands of immature ovarian follicles which start maturing when a girl reaches puberty stage.
    • One of the ovaries produces one ovum every month which is carried to the fallopian tube.
    • During sexual intercourse, if the ovum is fertilized by a sperm, then the fertilized ovum gets implanted in the lining (wall) of the uterus and develops into a hollow ball of cells called embryo.
    • The embryo obtains nutrition from the mother's blood through a tissue called placenta.
    • The development of child within uterus takes about nine months before it is born.
      
      
13. Write an explanatory note on menstrual cycle (or menstruation) in human female.
    ANS
    
    • When a girl reaches puberty stage at the age of 10-12 years, the sex hormones cause ova to become mature.
    • Every 28 days one mature ovum is released by ovary into the oviduct.
    • The process of release of ovum is called ovulation.
    • Before ovulation, the inner wall of the uterus becomes thick and full of blood capillaries.
    • Thus, it becomes prepared to receive fertilized ovum.
    • If fertilization does not take place during certain time, the wall of the uterus disintegrates and blood vessels break.
    • The disintegrated tissue and the dead ovum come out of the vagina along with blood.
    • This is known as menstruation which lasts for 3 to 5 days.
    • When menstruation is over, the inner wall of the uterus starts becoming thick again so that it may receive the next fertilized ovum.
    • If the ovum is not fertilized, the menstruation takes place again.
    • This menstruation cycle is repeated every 28 days.
    • If fertilization occurs and the woman becomes pregnant, then menstruation stops temporarily.
    • At the age of about 50 years, menstruation stops permanently.
    • This is called menopause and the woman loses the capability to reproduce.
      
      
14. Write a note on Reproductive Health.
    ANS
    
    • The diseases which are transmitted by sexual contact with an infected person are called Sexually Transmitted Diseases (STD).
    • Syphilis is caused by bacterial infection by bacteria Treponema palidium.
    • Lesions in mucus membrane of urinogenital tract and ulcers are symptoms of syphilis.
    • Gonorrhoea is caused by bacteria Neissena gonorrhoea. It results in inflammation of urinogenital tract.
    • Both syphilis and gonorrhoea are curable diseases.
    • AIDS (Acquired Immuno Deficiency Syndrome) is caused by HIV (Human Immuno-deficiency Virus).
    • AIDS damages the immune system of the body and weakens body's protection against infections.
    • AIDS is a fatal disease.
    • Research work is in progress to find out medicines to cure AIDS.
    • In India, NACO (National AIDS Control Organization) creates awareness regarding AIDS and provides information about reproductive health.
    • Multiple pregnancies adversely affect a woman's health.
    • Different methods have been devised to avoid unwanted pregnancy. These methods are called contraceptive methods.
15. Describe different methods of contraception (Birth control or Prevention of pregnancy)
    ANS
    
    • Contraceptive methods used for the birth control are of three types: (i) Mechanical method (ii) Chemical method (iii) Surgical method.
    • Mechanical method:
      In this method, the entry of sperms in the genital tract is prevented by creating a mechanical barrier. Due to this the fertilization of egg cannot occur. Condom worn on penis or diaphragm worn in vagina by female work as mechanical barriers. IUCDs (Intrauterine Contraceptive Devices) like copper-T placed in uterus prevent pregnancy.
      
      
    • Chemical method:
      Pills are used by female in this method. The oral pills contain hormones which stop the production of ova and prevent fertilization. Vaginal pills contain chemicals called spermicide which kill the sperms.
    • Surgical method:
      In male, a small portion of vas deferens is surgically removed and both the cut ends are tied properly. This prevents the entry of sperms to urethra. The process is called Vasectomy.
      In female, a small portion of oviduct is removed and tied up. This prevents ovum from entering the oviduct. The process is called Tubectomy.
      
      
16. 
    ANS
    

Chapter 16 : HEREDITY AND EVOLUTION

1. Define Sex Determination. What are the methods (mechanisms) of sex determination in different organisms?
   ANS
   
   • The mechanism to determine the sex of an individual is known as sex determination.
   • Different species use different mechanisms for sex determination.
     • In some species, the temperature at which fertilized eggs are kept determines whether the organism developing in the egg would be male or female.
     • In human beings the sex is determined genetically.
     • In animals like snail, the individual can change the sex, indicating that their sex is not determined genetically.
2. Answer in short.
   1. Name the ancestor of Broccoli, Kohlarabi, Kale, Cauliflower and Cabbage.
   2. Name at least two organisms which are now extinct and are studied from their fossils.
   3. Name five varieties of vegetables which have been produced from 'Wild cabbage' by the process of artificial selection.
   4. Choose the one term from the following which includes the other three: Broccoli, Wild cabbage, Cauliflower, Cabbage
   
   ANS
   
   1. Wild cabbage
   2. Ammonite, Trilobite, Dinosaur
   3. Broccoli, Kohlrabi, Kale, Cauliflower and Cabbage
   4. Wild cabbage
3. Explain : Variation.
   ANS
   
   • The occurrence of differences among the individuals of same species is known as variation.
   • Organisms which reproduce asexually or vegetatively show very little variation.
   • Organisms which reproduce sexually show distinct variations.
   • In sexual reproduction, crossing over of genes during meiosis gives rise to new combinations of characteristics. This results in variation among the individuals of species.
   • All these variations, however, do not have equal chance of survival in the environment in which they find themselves.
   • Different individuals get different advantages of these variations.
   • Selection of variants by environmental factors forms the basis of evolutionary process.
4. Write a note on Heredity.
   ANS
   
   • Heredity means continuity of features from one generation to another.
   • Heredity can be defined as "the transmission of characters from parents to the offspring" or "the tendency of every individual to resemble his/her parents".
   • Due to heredity, eggs laid by a sparrow hatch into sparrows only and a dog gives birth to pups only.
   • Hereditary information is present in the fertilized egg (zygote) which develops into an organism of a particular type only.
5. Write a note on Sex Determination.
   ANS
   
   • In humans, the sex is determined by the genes located on chromosomes.
   • Genes are inherited from parents.
   • Out of 23 pairs of chromosomes, 22 pairs are autosomes which are similar in male and female.
   • In female, the 23rd pair has two similar chromosomes called X-chromosome.
   • In male, one chromosome in 23rd pair is X chromosome and the other is Y chromosome which is smaller in size.
     
     
   • All eggs (ova) of female are similar. Each egg contains 22 autosomes and one X chromosome.
   • 50% sperms in male have X chromosome and 50% have the Y chromosome (along with 22 autosomes).
   • If a sperm carrying X chromosome fertilizes an egg, the zygote develops into a female.
   • If a sperm carrying Y chromosome fertilizes an egg, the zygote develops into a male.
6. Explain the following as Evidence of Evolution: (i) Homologous organs (ii) Analogous organs (iii) Fossils
   ANS
   
   1. HOMOLOGOUS ORGANS
      • The organs having the same internal structure but different functions are called homologous organs.
      • The basic design of the bones of forelimbs of a frog, a lizard, a bird, a bat and a man is similar in in their internal structure but they perform different functions.
      • This is an evidence that the forelimbs of all these organisms have evolved from a common ancestor with same basic internal structure.
   2. ANALOGOUS ORGANS
      • The organs with different basic design but similar appearance and similar function in different organisms are called analogous organs.
      • The wings of insects and the wings of birds have different structure but they perform similar function.
      • The presence of analogous organs in different animals give the evidence that they may not have evolved from a common ancestor but they perform similar function to survive in prevailing environment.
   3. FOSSILS
      • The impressions of dead organisms that lived in the past are known as fossils.
      • The dead bodies of organisms are decomposed by micro-organisms. Sometimes, due to environmental conditions, these bodies do not decompose completely and are preserved in the earth.
      • For example, a dead leaf trapped in mud is not decomposed completely and the mud forms impression of the leaf by setting around it as a mould. It then hardens to form a rock and retains the impression of the leaf. Thus, fossil of a leaf is formed.
      • The age of the fossils can be estimated by carbon dating method. The age is determined by the radioactive isotope of carbon (C-14).
      • Ammonite, Trilobite and Dinosaur are the examples of fossils. The age of their fossils is determined by carbon dating method.
7. Define 'Speciation'. Explain how speciation occurs.
   ANS
   
   • The process by which new species develop from the existing species is known as speciation.
   • When the population of a species splits into two groups separated geographically, new species are formed.
   • The geographical isolation leads to reproductive isolation and there is no gene flow between two separated groups of the population.
   • Some variation arises in individuals due to natural selection.
   • Due to the process of random change in gene frequency (genetic drift), the individuals (of two groups) become so different that they cannot reproduce with each other. This may take thousands of years.
   • There can be more ways like DNA changes, the change in the number of chromosomes, the inability of the germ cells of two isolated groups to fuse with each other, etc. which can lead to speciation.
   • Thus, new species come into existence.
8. Write a note on 'Expression of inherited characters' OR Explain how genes control characteristics.
   ANS
   
   • Gene is a unit of heredity.
   • Genes are located on DNA in a linear order.
   • Each gene synthesizes a specific protein responsible for the expression of a characteristic.
   • Consider the height of a plant as a characteristic. The height of a plant depends upon the amount of a particular growth hormone.
   • The synthesis of hormones is catalyzed by specific enzymes and the synthesis of enzymes is regulated by genes located on DNA.
   • If the enzyme is synthesized in large amount, a lot of hormone will be produced and the plant will be tall.
   • If the gene has an alteration that makes the enzyme less efficient, less hormone will be produced and the plant will be dwarf.
   • Thus, characteristics (traits) are controlled by genes.
9. Write a brief note on Evolution.
   ANS
   
   • Evolution is gradual formation of new species from pre-existing primitive organisms by constant and relatively long time changes.
   • Evolution is the sequence of gradual changes in primitive organisms from which new species have been formed.
   • It is a constant process that started since the origin of life and took millions of years. It is continuous and will occur in future, too.
   • The great variety of living organisms on earth is the result of evolution.
10. Explain : Acquired characteristics (traits).
    ANS
    
    • Acquired trait means a trait developed by an organism in response to the environment.
    • It is not inherited from parents.
    • For example, if the weight of an organism is reduced due to starvation, it would not change the DNA of germ cells. Thus, reduced weight is not a trait inherited by the future generation of starving organism.
    • Other examples of acquired traits are: (i) Cut tail of a mouse (ii) a man knowing how to swim (iii) a man speaking German language (iv) a scar on the body of a man due to accident.
    • These all are traits which cannot be passed on to the next generation as these are changes in non-reproductive cells of the body.
11. Explain : Inherited Characteristics (Traits).
    ANS
    
    • A trait of an organism caused by some change in its DNA is known as inherited trait.
    • Inherited traits can be passed on to the progeny of the organism.
    • Example: Suppose there is a population of red beetles in green bushes. If a colour variation arises during reproduction and a beetle green in colour is produced. Since this change is the result of a change in the DNA of reproductive cells, it is an inherited trait which can be passed on to the next generations.
    • This is the essence of the concept of evolution.
12. Write a brief note on Evolution of eyes.
    ANS
    
    • The eye is an important organ for animals.
    • It is a so complicated organ that it cannot have been generated by a single DNA change.
    • The eyes of animals have been created in stages over many generations.
    • First of all, eyes were formed in planaria (flat worm). These eyes were very simple just like 'eye spots' which could detect light.
    • These eyes provide a survival advantage to planaria.
    • The development of eyes seems to be a very popular adaptation.
    • The eyes in animals like insects, octopus, invertebrates and vertebrates have quite different structures suggesting that the evolution of eyes has occurred in stages.
13. Write a brief note on Evolution of Feathers.
    ANS
    
    • An evolutionary change produced in an organism for one purpose may later on become more useful for an entirely different function. Evolution of feathers is an example of this fact.
    • In some dinosaurs feathers provided insulation in cold weather but they could not be used for flying. Later, they might have become useful for flying.
    • Birds, however, adapted to flight. Thus, presence of feathers in birds indicates that birds are closely related to reptiles (like dinosaurs).
14. Explain : Evolution by Artificial Selection.
    ANS
    
    • The evidences for evolution suggest that very dissimilar looking structures can evolve from a common ancestor.
    • Different looking organisms can in fact be created from the same ancestor by artificial selection in place of natural selection.
    • The farmers have produced entirely different looking vegetables like cabbage, broccoli, cauliflower, kohlrabi and kale from the plant of wild cabbage by artificial selection.
    • Some farmers, in an attempt to have very short distance between the leaves of wild cabbage, produced the commonly used 'cabbage'.
    • Some farmers opted for the arrested flower development of wild cabbage and produced 'broccoli'.
    • Some farmers opted for sterile flowers of wild cabbage and developed 'cauliflower'.
    • When farmers opted for swollen parts of wild cabbage, it resulted in the evolution of 'kohlrabi'.
    • Those farmers who wanted to grow large leaves of wild cabbage produced a leafy vegetable called/kale'.
    • Thus, wild cabbage is the common ancestor and cabbage, broccoli, cauliflower, kohlrabi and kale are the varieties of wild cabbage which have been obtained by artificial selection.
15. Write a note on Human Evolution.
    ANS
    
    • To study human evolution tools like digging of earth, time-dating, study of fossils and DNA sequencing have been used.
    • There is a great variety of human forms and features across the earth.
    • This diversity of features was the basis of different human races. The human races were identified commonly on the basis of the colour of their skin. They were named as white, black, yellow and brown.
    • It is now a well-known fact that the sop called human races have not evolved differently. All human beings are a single species called 'Homo sapiens'.
    • It has been established scientifically that we lived for past few thousand years and our genetic footprint can be traced back to our African roots,i.e. we all came from Africa.
    • A couple of thousand years ago, some of our ancestors left Africa while others stayed back. Those who left Africa spread over the planet from Africa to different parts of Asia, Australia and America.
    • They went in groups, sometimes separating from one another and mixing with one another. Some of them even moved in and out of Africa.
    • This led to evolutionary changes like in all other species.
16. Explain Mendel's contribution.
    ANS
    
    • Mendel performed experiments for explaining the transmission of characteristics (traits) from parents to their offspring.
    • He performed experiments on Pisum Sativum (Garden Pea) and worked out the main rules of inheritance.
    • He studied the inheritance of some of the pairs of contrasting characters like tall and short plants, white and violet flowers, round and wrinkled seeds, axial and terminal flower positions, etc.
    • When Mendel crossed a tall plant (with TT traits on DNA) with a dwarf plant (with tt trait on DNA), the F₁ generation was found to be tall. There were no dwarf or medium height plants in F₁ generation. Thus, only one of the two parental characters was seen in F₁ generation.
    • When the plants of F₁ generation were used to obtain F₂ generation, 25% of the plants were dwarf and 75% were tall.
    • Thus, in F₁ generation both the characters of tallness and dwarfness were inherited from the parents but only the character of tallness was expressed because tallness was dominant trait and dwarfness was recessive trait. [Dominant trait is denoted by capital letter (T) and recessive trait bt small letter (t)].
    • The plants having TT or Tt traits for height were tall and those with tt trait were dwarf. A single trait T is enough for making a plant tall but for dwarfness tt traits are required.
      
      
    • In other experiment, Mendel selected two different traits in a plant. He crossed a plant having yellow and round seed with a plant having green and wrinkled seeds.
    • In F₁ generation, all the plants were with yellow and round seeds indicating that yellow and round are dominating traits.
    • When the plants of F₁ generation are self-pollinated, the plants along with parental combinations (yellow and round seeds, green and wrinkled seeds) new combinations (yellow and wrinkled seeds, grren and round seeds) are also formed in F₂ generation.
    • This indicates that yellow seeds/green seeds traits and round seeds/wrinkled seeds traits are independently inherited.
      
      
      
      
      
17. 
    ANS