CBSE Class 10 Science Heredity and Evolution VBQs

MCQ Questions for NCERT Class 10 Science Heredity and Evolution

Question. Variations may be due to
(a) mutation
(b) environmental factors
(c) cell division
(d) all of the above
Answer : D

Question. Struggle for existence was explained by
(a) Lamarck
(b) Hugo de Vries
(c) CharlesDarwin
(d) none of the above
Answer : C

Question. Gene mutation means
(a) change in base pairs of the gene
(b) addition of a base pair in the gene
(c) removal of a base pair in the gene
(d) all of the above
Answer : D

Question. Who was not involved in the study of the origin of life?
(a) Miller
(b) Urey
(c) Morgan
(d) Oparin
Answer : C

Question. Heredity is opposed by
(a) variation
(b) environment
(c) genes
(d) none of the above
Answer : A

Question. Inheritance of acquired characters refers to
(a) inheritance of adaptive and nonadaptive characters
(b) inheritance of somatic characters as well
(c) inheritance of germinal variations
(d) none of the above
Answer : B

Question. The Genotype of offspring formed from Tt#tt will be-
(a) TT and tt
(b) Tt and tt
(c) only tt
(d) only TT
Answer : B

Question. Which of the following rediscovered the Mendel’s work?
(a) Correns
(b) de Vries
(c) Tschermark
(d) all of the above
Answer : D

Question. Gene is made of which chemical
(a) D.N.A.
(b) R.N.A.
(c) protein
(d) enzyme
Answer : A

Question. Which of the following is Heterozygous?
(a) TTRR
(b) ttrr
(c) TT
(d) Tt
Answer : D

Question. In natural selection,
(a) the genetic composition of the population changes at random over time.
(b) new mutations are generated over time.
(c) all individuals in a population are equally likely to contribute offspring to the next generation.
(d) individuals that possess particular inherited characters survive and reproduce at a higher rate than other individuals.
Answer : D

Question. Which statement about the genotypes of organisms is correct?
(a) Dominant alleles are only found in homozygotes
(b) One recessive allele always causes a recessive phenotype
(c) Recessive phenotypes must be homozygous
(d) The dominant phenotype msut be heterozygous
Answer : C

Question. An example of homologous organs is
(a) our arm and a dog’s fore-leg.
(b) our teeth and an elephant’s tusks.
(c) potato and runners of grass.
(d) all of the above.
Answer : D

Question. A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent can be depicted as
(a) TTWW
(b) TTww
(c) TtWW
(d) TtWw
Answer : C

Question. In evolutionary terms, we have more in common with
(a) a Chinese school-boy.
(b) a chimpanzee.
(c) a spider.
(d) a bacterium.
Answer : A

Question. Which statement describes an example of artificial selection?
(a) It has been found that some strains of bacteria produce antibiotics
(b) It is common practice to mate bulls with cows that produce the most milk
(c) It is possible to control caterpillars on food crops by releasing small wasps which lay their eggs on caterpillars and kill them
(d) Mosquitoes have developed strains that are resistant to insecticides
Answer : B

Question. Which of the following provides evidence for evolution?
(a) Direct observations of genetic changes in populations
(b) Shared characteristics of organisms
(c) The fossil record
(d) All of the above
Answer : D

Question. The phenomenon by which a new set of population is formed from the change in frequency of some genes is
(a) genetic drift
(b) organic evolution
(c) variations
(d) speciation
Answer : A

Question. What determines the sexs of a child?
(a) Chromosome content of the ovum
(b) Chromosome content of the sperm
(c) Number of days between ovulation and fertilisation
(d) Number of days between fertilisation and implantation
Answer : B

Question. When a breed of cattle with red coats is crossed with the same breed with white coats, all the offspring have coats with a mixture of red and white hairs, a condition called roan.
If roan cows were crossed with a red-coated bull, the theoretical ratio of the offspring would be
(a) all red
(b) all roan
(c) 1 red : 1 roan
(d) 3 red : 1 roan
Answer : C

Question. Fossils are the remains of
(a) hard parts of life forms in rock
(b) soft parts of life forms in rock
(c) protein and bones of life forms
(d) None of the above
Answer : A

Fill in The Blank

Question. There is no possibility of chemical evolution of life on earth today, because .........
Answer : The atmosphere is oxidising

Question. The homologous organs have different functions but have .......... structures.
Answer : Similar

Question. The two types of reproduction are sexual and ..........
Answer : Asexual

Question. An atmosphere rich in hydrogen is an ......... atmosphere.
Answer : Reducing

Question. Wind of bat and wing of bird are the example of the ......... organs.
Answer : Analogous

Question. The study of fossils, a branch of biology called ........ was founded by Goerges Cuiver.
Answer : Paleontology

Question. The first organisms were .......... and not autotrophs.
Answer : Heterotrophs

Question. Theory of natural selection was proposed by .........
Answer : Darwin

Question. The traits which are acquired by an organism during its lifetime are called .......... .
Answer : Acquired traits

Question. .......... and .......... proved that life originated from inorganic molecules.
Answer : Stanley Miller and Harold Urey

Question. The theory of natural selection was given by ..........
Answer : Darwin

Question. Forelimbs of frog and lizard are the example of the ......... organs.
Answer : Homologous

Question. The phenotypic in dihybrid cross is .........
Answer : 9 : 3 : 3 : 1

Question. Fossils are written documents of .......... .
Answer : Evolution

Question. .......... are the chromosomes found in somatic cells.
Answer : autosomes

Mark the statements true(T) or false(F).

Question. Most mutations are beneficial.
Answer : true

Question. Mutation can occur due to X-rays.
Answer : true

Question. Genes do not maintain their purity, said Mendel.
Answer : false

Question. Nature selects favourable characters and eliminates unfavourable ones. 
Answer : true

Question. Selection of variants by environmental factors forms the basis of evolutionary process.
Answer : True

Question. The atmosphere of the primitive earth was reducing.
Answer : True

Question. Variations arising during the process of reproduction cannot be inherited.
Answer : False

Question. Life can originate on earth from pre-existing life only.
Answer : True

Question. Sex of the child is determined by the type of ovum provided by the mother.
Answer : False

Question. The more characteristics two species will have in common, the more closely they are related.
Answer : True

Question. Evolution cannot be said to ‘progress’ from ‘lower’ forms to ‘higher’ forms.
Answer : True

Question. Traits which are not inherited over generations do not cause evolution.
Answer : True

Question. Reduction in weight of the organism due to starvation is genetically controlled.
Answer : False

Question. A recessive trait can also be common as blood group O.
Answer : True

Case study questions

I Read the given information and answer the following questions.
Pea plants can have smooth seeds or wrinkled seeds. One of the phenotypes is completely dominant over the other. A farmer decides to pollinate one flower of a plant with smooth seeds using pollen from plant with wrinkled seeds. The resulting pea pod has all smooth seeds.

Question. Which of the following conclusions can be drawn?
(1) The allele for smooth seeds is dominated over that of wrinkled seeds.
(2) The plant with smooth seeds is heterozygous.
(3) The plant with wrinkled seeds is homozygous.
(a) 1 only
(b) 1 and 2 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer : C

Question. Which of the following crosses will give smooth and wrinkled seeds in same proportion?
(a) RR X rr
(b) Rr X rr
(C) RRX Rr
(d) rr X rr
Answer : B

Question. Which of the following cross can be used to determine the genotype of a plant with dominant phenotype?
(a) RR X RR
(b) Rr X Rr
(c) Rr X RR
(d) RR X rr
Answer : D

Question. On crossing of two heterozygous smooth seeded plants (Rr), a total of 1000 plants were obtained in F1 generation. What will be the respective number of smooth and wrinkled seeds obtained in F1 generation?
(a) 750, 250
(b) 500, 500
(C) 800, 200
(d) 950, 50
Answer : A

Very Short Answer Type Questions

Question. Name one trait which is inherited and one trait which is acquired.
Answer : Inherited trait – Eye colour in humans
Acquired traits – Reduction in body weight of an animals due to starvation.

Question. Why is the progeny always tall when a tall pea plant is crossed with a short pea plant?
Answer : When a tall pea plant is crossed with a short pea plant, the resultant progeny is always tall because tallness is a dominant trait while shortness is a recessive trait. Hence,
dominant trait expresses itself in the progeny.

Question. Name two human traits that show variations.
Answer : Colour of eyes and shape of external ears.

Question. What is a gene?
Answer : Gene is the unit of inheritance. It is a segment of the chromosome which controls hereditary characteristics.

Question. Give an example where sex determination is regulated by environmental factors.
Answer : In garden lizards, sex of the organism is determined by environmental factor such as temperature.

Question. How many pairs of allelic characters did Mendel study in pea plant?
Answer : Mendel studied seven pairs of allelic characters in pea plant.

Question. All the variations in a species do not have equal chances of survival. Why?
Answer : All the variations do not have equal chances of survival in the environment in which they live. Depending on the nature of variations, different individuals would have different
kinds of advantages. The organisms which are most adapted to the environment will survive.

Question. Sex chromosomes of human males are dissimilar. Justify.
Answer : Human males have XY sex chromosomes, where X chromosome is morphologically distinct from Y chromosome. Y chromosome is smaller than X chromosome. Hence, they
are dissimilar or heteromorphic.

Question. What do you mean by a true breeding plant?
Answer : A true breeding plant is the one that when self-fertilised, produces offspring with the same traits. They will be either homozygous dominant or homozygous recessive.

Question. How do genes control traits? 
Answer : Genes carry information for the the production of proteins which, on the other hand, control the various body characteristics.

Short Answer Type Questions

Question. “The chromosome number of the sexually reproducing parents and their offspring is the same.” Justify this statement.
Answer : Gametes formation involves meiosis or reduction division. The gamete mother cell is diploid (2n), i.e., it has two sets of chromosomes. This single diploid cell divides by
meiosis to form 4 haploid (n) daughter cells. Each daughter cell becomes a gamete, either male or female. Each gamete possesses single set of chromosomes. Fusion of these
gametes results in the formation of a zygote having a double set of chromosomes i.e., diploid (2n) (one set of paternal and the other set maternal). Thus the number of chromosomes
in parents and offsprings of a particular species remains constant.

Question. A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?
Answer : No, we cannot say that the traits is recessive or dominant unless we know the nature of the two variants of a trait.

Question. Explain the importance of fossils in deciding evolutionary relationships.
Answer : Fossils help us to know the following:
(a) Fossils help to trace the racial history of organisms.
(b) They help to measure the geological time.
(c) Older fossils lie at the depth and young fossils are at the upper surface of the earth. Complex organisms are present at top and simple organisms are present at the bottom.
(d) Fossil like—Archaeopteryx-show the link between two different types of species.

Question. Explain the terms analogous and homologous organs with examples.
Answer : Analogous organs—Organs with different structure and same function e.g., wings of bird, insects.
Homologous organs—Organs which have same structure but different functions are called homologous organ e.g., forearm of lizard, bird and human.

Question. Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with this statement? Why or why not?
Answer : No, depending on the nature of variations different individuals have different kinds of advantages. However, when a drastic change occurs in environment only those organism in the population will survive which have an advantageous variation in that population to survive in changed environment.

Question. What evidence do we have for the origin of life from inanimate matter?
Answer : Miller and Urey in 1953 assembled an atmosphere similar to that thought to exist at early period (Gases like ammonia, methane, hydrogen sulphide) over earth. This was maintained at a temperature just below 100°C and sparks were passed through the mixture of gases to simulate lighting. At the end of a week 15% of the carbon (from methane) had been converted to simple compounds of carbon including amino acids which make up protein molecules. Presence of protein cell membrane correlates with above experiment. This shows that life originated from inanimate matter.

Question. Outline a project which aims to find the dominant coat colour in dogs.
Answer : Dominant → WW (white colour)

Question. How is the equal genetic contribution of male and female parents ensured in the progeny?
Answer : By studying the crossing over of genes of male sex and female sex is as follows:

Question. How are the areas of study—evolution and classification—interlinked?
Answer : For c lassification of organisms we generally group the organisms of same characteristics together and those with different characteristics are grouped or classified separately. A set of characteristics tells about the level of evolution of an organism.

Question. Explain how sexual reproduction gives rise to more viable variations than asexual reproduction. How does this affect the evolution of those organisms that reproduce sexually?
Answer : Variations are seen more in sexual reproduction than asexual reproduction because variations occur due to change in DNA coding and due to sexual reproduction in which two genes from two different sexes i.e., male and female genes crossing over takes place and hence cause the variation.

Question. Explain in brief how Mendel interpreted his results to show that the traits may be dominant or recessive.
Answer : When Mendel crossed two pea plants with a pair of contrasting characters only one character appeared in all the members of F₁ progeny, the other was not expressed.
On selfing F₁, the hidden characters reappeared in just 25% of the offsprings and the other 75% shared the characters expressed in F₁. Mendel concluded that the character which expresses itself in F1 and in 75% of the individuals of F₂ is dominating while the other is recessive.

Question. How do proteins control the expression of characters? Explain it by taking an example of tallness in plants as a characteristic.
Answer : Plants have hormones that can trigger growth. Plant height can depend on the amount of a particular plant hormone. The amount of the plant hormone produced will depend on the efficiency of the process for making it. An enzyme (chemically protein molecules) that is important for this process, if works efficiently, a lot of hormone will be produced, and the plant will be tall. If the gene for that enzyme has an alteration that makes the enzyme less efficient, the amount of hormone will be less, and the plant will be short. Thus, enzymes which are protein in nature control the expression of characters.

Question. Crossing of a pea plant with purple flower and pea plant with white flowers, produces 50 plants with only purple flowers. On selfing, the plants produced 470 plants with purple flowers and 160 with white flowers. Explain the genetic mechanism accounting for the above results.
Answer : In this breeding experiment, ratio of purple to white flowers is approximately 3 : 1 in F2 generation. So the ratio is according to Mendelian monohybrid cross. The cross further explains the following facts:
(i) F1 is represented only by dominant trait, i.e., purple flowered plants.
(ii) Both the traits, i.e., purple and white flower colour show segregation and thus appear in F2 generation.

Question. Explain the law of purity of gametes.
Answer : Principle of purity of gametes is also known as principle or law of segregation. According to this law, the two unit factors of a character which remains together in an individual do not get mixed up and keep their distinct identity. They separate during gamete formation so that each gamete receives only one factor or gene for each character and is
always pure.

Question. Differentiate between inherited and acquired traits.
Answer : Differences between inherited and acquired traits are as follows : 

Question. In the following crosses write the characteristics of the progeny.  

Answer : (a) When two plants with round yellow seeds are crossed, the progeny produced will also possess round yellow seeds. 
(b) When plants heterozygous for round seed shape and yellow seed colour are crossed following progenies will be produced :

Parents RrYy RrYy
(Round, yellow) (Round, yellow)
F₁ generation
The progeny produced will posses round yellow, round green, wrinkled yellow, and wrinkled green seeds in the ratio of 9 : 3 : 3 : 1.

Question. “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.
Answer : Sex is determined at the time of fertilisation when male and female gametes fuse to form zygote. Male produces two types of gametes, i.e., having X or Y chromosome and female produces one type of gametes all containing X chromosomes. If a sperm (male gamete) carrying X chromosome fertilises an egg or ovum (female gamete) carrying X chromosome, then the offspring will be a girl (female). This is because the offspring will have XX combination of sex chromosomes. If a sperm (male gamete) carrying Y chromosome fertilises an egg or ovum (female gamete) which has X chromosome, then the offspring will be a boy (male). This is because the offspring will have XY combination of sex chromosomes. Therefore, there is 50% chance of a male child and 50%chance of a female child. 21

Question. In which generation does the segregation of allelic phenotype takes place?
Answer : In F₁ generation both alleles come together in hybrid but only dominant character is expressed. In F₂ generation, on selfing of F1 hybrids, these alleles segregate. As a result,
dominant (pure and hybrid) and recessive (pure) phenotypes are segregated.

Question. The genotype of green stemmed tomato plants is denoted as GG and that of purple stemmed tomato plants as gg. When these two are crossed :
(i) What colour of stem would you expect in their F1 progeny ?
(ii) Give the percentage of purple-stemmed plants if F1 plants are self pollinated.
(iii) In what ratio would you find the genotypes GG and Gg in the F2 progeny?
Answer : (i) In F₁ progeny all tomato plants will be green stemmed with genotype Gg.
(ii) 25% of plants will be purple stemmed in F2 generation which are produced due to self pollination of F1 plants.
(iii) In F₂ progeny ratio of GG to Gg will be 1 : 2 and will be green stemmed.

Question. How do germ cells make a single set of genes from two normal copies of genes?
Answer : There is a pair of genes for a particular trait. The genes controlling a particular trait separate from each other during gamete formation. Germs cells make a single set of genes from two normal copies by a process called meiosis or reduction division. Hence gamete is always pure as far as contrasting characters are considered and will possess only
one gene set. When male and female gametes fuse during fertilisation, paired condition is restored.

Question. “Different species use very different strategies for determining the sex of their new born.” Justify this statement.
Answer : In some animals, environmental factors such as association with families, egg size and incubation temperature determine the sex of the individuals. For example, in lizards
the temperature at which fertilised eggs are kept, determines whether the developing animal in fertilised egg is male or female. In some animals, like snail, individual can change
sex. However, in some animals, sex of individuals determined genetically by specific chromosomes. For example in humans, if a child inherits X-chromosome from the father, will be a girl and one who inherits a Y-chromosome from the father will be a boy.

Question. A man having blood group O marries a woman having blood group B and they have a daughter. What will be the blood group of the daughter?
Answer : 

The blood group of the daughter be either B or O depending upon the blood group of mother.

Question. Why do all the gametes formed in human females have an X chromosome?
Answer : Genotype of human female is 44 + XX. Human female is homogametic. During meiosis, at the time of gamete formation, only one X chromosome enters in each gamete.
Hence, all female gametes have genotype (22 + X).

Question. An individual inherits different traits from his parents. On what basis classification of traits as dominant and recessive is done?
Answer : A trait which is able to express itself both in homozygous as well as heterozygous conditions is called a dominant trait, e.g., tallness is a dominant trait in pea plant. A trait which expresses itself only in homozygous condition, but remains suppressed in heterozygous condition is called recessive trait, e.g., dwarfness is the recessive trait in a pea plant.

Question. Which type of organisms will have more variations – sexually or asexually reproducing organisms? 
Answer : Sexually reproducing organisms will show more variations as genetic material is exchanged between homologous pair of chromosomes during crossing over. However, during asexual reproduction, mutations are the only means of variations during DNA replication which are not very common and thus may lead to very little variation.

Question. Give reasons for the appearance of new combinations of characters in the F2 progeny.
Answer : A breeding experiment dealing with two characters at the same time is called a dihybrid cross. In such a cross only one parental combination appears in F1 generation. However, in F2 generation raised by self pollination, four combinations of traits appear. These include two parental types and two new combinations. A typical dihybrid cross in pea plant is depicted as follows : 26
New combination of characters appear in F2 generation because the inheritance of factors controlling a particular trait in an organism are independent of each other. This is called
law of independent assortment. At the time of reproduction, two pairs of factors of each of the two traits in a dihybrid cross segregate independently during gamete formation and
randomly form combinations in F2 generation.

Question. Explain with an example, how genes control the characteristics (or traits).
Answer : The genes control the characteristics by making a specific protein. Genes are the segment of DNA that contains information to form RNA which ultimately forms protein. Each
gene contains two alleles and this instruct the cell to make protein for expression of traits. For example, if the plant has genes for violet flower, then it will make protein which will
give violet colour to flowers.

Question. The gene for red hair is recessive to the gene for black hair. What will be the hair colour of a child if he inherits a gene for red colour from his mother and a gene for black hair from his father? Express with the help of flow chart.
Answer : The hair colour of child will be black. This can be illustrated as follows: 

Question. Differentiate between genotype and phenotype.
Answer : Differences between genotype and phenotype are as follows : 

Question. (a) State one advantage of variation to a species.
(b) What are sex chromosomes? How many sex chromosomes are there in humans? Name them.
Answer : (a) Variation increases the chance of the species survival in a changing environment.
(b) A sex chromosome is a type of chromosome that participates in sex determination. Humans have two sex chromosomes, X and Y.

Question. After self-pollination in pea plants with round, yellow seeds, following types of seeds were obtained by Mendel:
Analyse the result and describe the mechanism of inheritance which explains these results.
Answer : In Mendel’s dihybrid cross, with yellow round and green wrinkled seeds 9 : 3 : 3 : 1 ratio was obtained showing four phenotypes. Yellow colour was originally present with round seeds but in F₂ generation it was assorted independently of round seed character and expressed with wrinkled seeds. Same is the case with green colour. Thus, it shows independent assortment of characters.

Long Answer Type Questions

Question. Write the basic features of mechanism of inheritance. How do Mendel’s experiment show that traits are inherited independently?
Answer : The basic features of mechanism of inheritance are as follows:
(i) Characters are controlled by genes and each gene controls one character.
(ii) Chromosomes are gene carrier and genes are basic unit of heredity.
(iii) One form of gene may be dominant on other, i.e., genes are allelic in nature.
(iv) The two forms of alleles separate at the time of gamete formation, i.e., they do not mix with each other.
(v) Two allelic forms of a gene are brought together in zygote.
Traits are inherited independently can be explained by dihybrid cross. A cross is made between a pure round yellow seeded pea plant (RRYY) with wrinkled green seeded pea plant
(rryy). Yellow colour is dominant over green and rounded seed shape over wrinkled seed shape. F1 plants are all round and yellow seeded. F₁ plants are self breed and produce F₂
generation. F₂ generation has four types of plants: rounded yellow, rounded green, wrinkled yellow and wrinkled green in the ratio of 9:3:3:1 respectively.
Each of the characters if considered separately shows a ratio of 3:1 as found in monohybrid cross. The F₂ ratio of 9:3:3:1 shows two types of recombinants, wrinkled yellow and rounded green. They can be produced only if the alleles of the two different characters are free to recombine, i.e., separate and combine independent to each other.

Question. Plant with full green pod is said to be homozygous dominant. Plant with constricted yellow pod is said to be homozygous recessive.
Crossing of these two plants can also give rise to plants with full yellow pod. Plants with constricted green pod are also produced.
(i) What conclusion could Mendel draw from this observation?
(ii) Work out a cross upto F2 generation for such type.
Answer : (i) The plants obtained on crossing the given plants can have different combination as gametic fusion can take place in any manner (both parental combination and recombination) are possible, which proved that both the traits of the two characters are assorted independently, and hence, plants with different kind of pods are produced. 

Question. Explain determination of sex among human beings, with the help of a diagram.
Answer : Diploid organisms like human beings have separate sexes. In organisms, where sex is determined genetically, a pair of chromosomes called sex chromosomes determines
the sex of the individual. All other chromosomes are termed autosomes. In human beings, there are 46 chromosomes. Of these, one pair is of sex chromosomes which are of two types
– X chromosome and Y chromosome.
(i) A male individual contains one X chromosome and one Y chromosome i.e., XY.
(ii) A female contains two X chromosomes i.e., XX.
The sex of the child is determined at the time of fertilisation when male and female gametes fuse to form zygote. It can be shown as follows: 

Question. A blue colour flower plant denoted by BB is cross-bred with that of white colour flower plant denoted by bb.
(i) State the colour of flower you would expect in their F₁ generation plants.
(ii) What must be the percentage of white flower plants in F₂ generation if flowers of F₁ plants are self-pollinated?
(iii) State the expected ratio of the genotypes BB and Bb in the F₂ progeny.
Answer : (i) : The colour of the flower in F₁ generation will be blue with Bb genotype.
(ii) If the flowers of F₁ generations are self pollinated, then the percentage of white flowers in F₂ generation must be 25%.
(iii) The expected ratio of the genotypes BB and Bb in the F₂ progeny is 1 : 2.
The above results could be depicted by the given cross:  

Read the following and answer the following questions from Refer to the schematic representation of the albinism that is an inherited condition caused by recessive allele (a). ‘A’ is the dominant allele for the normal condition. The inheritance of certain genetic traits for two or more generations is represented in a pedigree or family tree. Study the given pedigree chart and answer the following questions. 

Question. If Y married a normal homozygous male, then what is the probability that their children would be albino?  
(a) 0
(b) 0.125
(c) 0.25
(d) 0.5

Answer : A

Question. Which of the following could be the genotype of offsprings produced by cross of X and Y?  
(a) AA, Aa, aa
(b) aa, aa
(c) Aa, Aa
(d) AA, AA

Answer : A

Question. Which of the following could be the genotypes of X and Y?  
       X   Y
(a) AA AA
(b) AA Aa
(c) Aa Aa
(d) aa aa

Answer : C

Question. Which of the following could be the genotype of generation - 1 male and female?  
   Male  Female
(a) AA aa
(b) aa AA
(c) Aa aa
(d) AA AA

Answer : B

Question. If X married an albino female, then what is the probability that their children would be albino?   
(a) 0
(b) 0.125
(c) 0.25
(d) 0.5

Answer : D

Read the following and answer the following questions from Refer to the given table regarding results of F₂ generation of Mendelian cross. 

Question. Which of the following will result when plant YyRr is self-pollinated?  
(a) 9 : 3 : 3 : 1 ratio of phenotypes only
(b) 9 : 3 : 3 : 1 ratio of genotypes only
(c) 1 : 1 : 1 : 1 ratio of phenotypes only
(d) 1 : 1 : 1 : 1 ratio of phenotypes and genotypes

Answer : A

Question. The percentage of yR gamete produced by YyRR parent will be  
(a) 25%
(b) 50%
(c) 75%
(d) 12.5%

Answer : B

Question. Which of the following would be the phenotype of F₁ generation regarding given data of F₂ generation?   
(a) Plants with round and yellow coloured seeds.
(b) Plants with round and green coloured seeds.
(c) Plants with wrinkled and yellow coloured seeds.
(d) Plants with wrinkled and green coloured seeds.

Answer : A

Question. Which of the following would be the genotype of parental generation regarding given result of F2 generation?  
(a) YYRR and yyrr
(b) YYRR and YYRR
(c) YYRR and YyRr
(d) YyRr and YyRr

Answer : A

Question. If plant with wrinkled and green coloured seeds (S) is crossed with plant having wrinkled and yellow coloured seeds (R), what will be the probable phenotype of offsprings?  
(a) All plants with wrinkled and yellow coloured seeds.
(b) 50% plants with wrinkled and yellow coloured seeds and 50% plants with wrinkled and green coloured seeds.
(c) All plants with wrinkled and green coloured seeds.
(d) Both (a) and (b)

Answer : D