CBSE Class 12 Biology Question Paper (Delhi 2013) with Solutions

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CBSE Class 12 Biology Question Paper (Delhi 2013) with Solutions

Time Allowed: 3 Hours

General Instructions:

1. All questions are compulsory.
2. This question paper consist of four Sections A, B, C and D. Section A contains 8 questions of one mark each, Section B is of 10 questions of two marks each, Section C is of 9 questions of three marks each and Section D is of 3 questions of five marks each.
3. There is no overall choice. However, internal choice has been provided in one question of 2 marks, one question of 3 marks and two questions of 5 marks weightage. A student has to attempt only one of the alternatives in such questions.
4. Wherever necessary, the diagrams drawn should be neat and properly labelled.

Section – A

Question 1.
An anther with malfunctioning tapetum often fails to produce viable male gametophytes. Give any one reason.
Answer:
Tapetum provides nourishment to the developing pollen grain and a malfunctioned tapetum fails to produce viable male gametes as they lack nourishment.

Note
Tapetum is the innermost layer of microsporangium and cells of the tapetum possess dense cytoplasm and generally have more than one nucleus.

Question 2.
Why sharing of injection needles between two individuals is not recommended?
Answer:
Sharing of injection needles is not recommended between two individuals because it leads to the transmission of fatal and incurable diseases such as hepatitis B and AIDS that can be transmitted from one person to another on coming in contact with the body fluid of an infected person.

Question 3.
Name the enzyme and state its property that is responsible for continuous and discontinuous replication of the two strands of a DNA molecule.
Answer:
An enzyme DNA-dependent DNA polymerase is responsible for the continuous and discontinuous replication of the DNA strand. DNA-dependent DNA polymerase enzyme catalyses the polymerisation of DNA in only one direction such as from 5’→3’ and is called coding strand and is discontinuous. Whereas the complementary strand Having polarity 3’→5’ is called antisense strand and is continuous.

Note
The discontmuously synthesised fragments arc joined together by an enzyme DSA ligase.

Question 4.
Identify the examples of convergent evolution from the following:
(i) Flippers of penguins and dolphins
(ii) Eyes of octopus and mammals
(iii) Vertebrate brains
Answer:
(i) Flippers of penguins and dolphin is an example of convergent evolution and are analogous structures.

(ii) Eyes of octopus and mammals are also an example of convergent evolution as the structures are analogous structures.

Note
Analogous structures are those that are not anatomically similar structures but perform similar functions.

(iii) Vertebrate brain is an example of divergent evolution and is homologous organ.

Question 5.
Write the importance of MOET.
Answer:
MOET stands for Multiple Ovulation Embryo Transfer. This technology has been demonstrated for cattle, sheep, rabbits, buffaloes, mares and so on in order to increase the high milk yielding breeds of females. It also helps in the formation of high quality (lean meat with less lipid) meat- yielding bulls that have been bred successfully in order to increase the herd size in a shorter time.

Question 6.
Why is the enzyme cellulase needed for isolating genetic material from plant cells and not from the animal cells?
Answer:
Plants cells have cellulose in their cell wall that can be degraded by cellulase enzyme in order to isolate DNA. While in case of animal cell, cell wall is absent and due to this, cellulase enzyme is not required for isolation of DNA.

Note
Lysozyme enzyme is used for breaking bacterial cell whereas chitinase enzyme is usedfor breaking fungal cells.

Question 7.
Name the type of biodiversity represented by the following:
(a) 50,000 different strains of rice in India
(b) Estuaries and alpine meadows in India.
Answer:
(a) The availability of 50,000 genetically different strains of rice is an example of genetic diversity. Genetic diversity is produced due to difference in soil found in different regions. It is also occurs due to different agricultural practices as well as use of various horticulture techniques that are used in India.

Note
Genetic diversits is defined as the type of diversity in which the number and types of genes as sell as chromosomes that are found in different species. It leads to sanation m the genes and their alleles in the same species. It leads to speciation as well as evolution of new species.

(b) The availability of estuaries and alpine meadows in India is an example of ecological diversity. India has a greater ecosystem diversity than a Scandinavian country like Norway.

Note
Ecological diversity is defined as the type of biodiversity which involves the variation in the ecosystems that are found in a region or the variation in ecosystems over the whole planet.

Question 8.
Write the equation that helps in deriving the net primary productivity of an ecosystem.
Answer:
Net primary productivity is defined as the Gross primary productivity (GPP) minus respiration losses (R).
NPP = GPP – R
Where Gross primary productivity of an ecosystem is defined as the rate of production of organic matter during photosynthesis.

Note
Productivity refers to the rate of biomass production whereas primary productivity refers to the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis.

Section – B

Question 9.
Geitonogamous flowering plants are genetically autogamous but functionally crosspollinated. Justify.
Answer:
Geitonogamy involves the transfer of pollen grains from the anther to the stigma of another flower of the same plant. Geitonogamy is functionally cross-pollination that involves pollinating agent but genetically is similar to autogamy since the pollen grains come from the same plant.

Note
Autogamy is a type of self-pollination in which pollination is achieved within the same flower. In this, transfer of pollen grains from the anther to the stigma of the same flower.

Question 10.
When and where do chorionic villi appear in humans? State their function.
Answer:
After implantation, finger-like projections appear on the trophoblast called chorionic villi. It is surrounded by the uterine tissue and maternal blood. The chorionic villi and uterine tissue become interdigitated with each other and jointly form a structural and functional unit between the developing embryo or foetus and maternal body called placenta.

Note
Chorionic villi make up a significant portion of the placenta and serve primarily to increase the surface area by which products from the maternal blood are made available to the fetus.

Question 11.
In a cross between two tall pea plants some of the offsprings produced were dwarf. Show with the help of Punnett square how this is possible.
Answer:
The given cross represents in a form of Punnett square are as follows:

When two heterozygous tall parents are crossed, three heterozygous tall and one dwarf plant is obtained.

Note
Punnett square-was developed by a British geneticist, Reginald C.Punnett and is defined as a graphical representation for calculation of probability of all the possible genotypes of offsprings in a genetic cross.

Question 12.
A student on a school trip started sneezing and wheezing soon after reaching the hill station for no explained reasons. But, on return to the plains, the symptoms disappeared. What is such a response called? How does the body produce it?
Answer:
The student is suffering from allergy and the substances to which such an immune response is produced are called allergens. Allergy is because of the release, of chemicals such as histamine and serotonin from the mast cells.

Note
The antibodies produced to allergic response are of IgE type.

Question 13.
Name two commonly used bioreactors. State the importance of using a bioreactor.
Answer:
The two commonly used bioreactors are stirred-tank bioreactor and sparged stirred-tank bioreactor.
A stirred-tank bioreactor is cylindrical or with a curved base in order to facilitate the mixing of reactor contents and stirrer facilitates the mixing and availability of oxygen throughout the bioreactor.

Alternatively air can be bubbled through the reactor. Whereas in a sparged stirred-tank bioreactor, a sparge which is a ring made of metal or glass that facilitates the mixing and oxygen availability throughout the bioreactor.

Bioreactors are important as large volume (100-1000 litres) of culture can be processed. Bioreactor provides optimal conditions for growth such as temperature, pH, substrate, salts, vitamins and oxygen for production of desired product.

Note
Bioreactors are the large vessels in which raw materials are biologically converted into specific products such as enzymes, proteins by using animal cells, plant cells or microbes.

Question 14.
Write the function of adenosine deaminase enzyme. State the cause of ADA deficiency in humans. Mention a possible permanent cure for a ADA deficiency patient
Answer:
ADA deficiency is caused because of the deletion of the gene that code for adenosine deaminase enzyme. Severe combined Immunodeficiency disorder (SCID) is caused because of the defect in gene which codes for adenosine deaminase enzyme. The enzyme plays crucial role in the proper functioning of immune system.

ADA (Adenosine deaminase deficiency) can be treated by enzyme replacement therapy in which functional ADA is given to the patient by injection. In this process:

• Lymphocytes from the blood of the patients are grown in a culture outside the body.
• A functional ADA cDNA (using a retroviral vector) is then introduced into these lymphocytes which are subsequently returned to the patient.

Disadvantages associated with enzyme-replacement therapy are:

• This method is not completely curative.
• The cells are immortal as the patients require periodic infusion of such genetically engineered lymphocytes.

ADA deficiency can be permanently cured if gene isolates from marrow cells produces ADA is introduced into cells at early embryonic stages.

Note
The first clinical gene therapy was given in 1990 to a 4-year old girl suffering from adenosine deaminase (ADA) deaminase.

Question 15.
Expand the following and mention one application of each:
(i) PCR
(ii) ELISA
OR
(a) Mention the difference in the mode of action of exonuclease and endonuclease.
(b) How does restriction endonuclease function ?
Answer:
(i) PCR stands for Polymerase Chain Reaction. It is a molecular biology technique used for the synthesis of many copies of a specific DNA Invitro. It is used for the diagnosis of infectious diseases even if the sample is present in minute quantities.
PCR requires sets of primers (small chemically synthesised oligonucleotides that are complementary to the regions of DNA) and Enzyme Taq DNA polymerase.

Note
The enzyme Taq DNA polymerase is a thermostable enzyme as it can tolerate higher temperature (upto 96 °C) as it is extracted from a bacterium Thermits aquaticus.

(ii) ELISA stands for Enzyme Linked Immunosorbent Assay is a molecular biology and immunological technique used for the diagnosis of AIDS. It is used for the measurement of antibodies in the blood and the test can be used for the determination of antibodies in the blood during infection. (2 Marks)

Note
The enzyme used in ELISA is horseradish peroxidise.

OR

(a) Restriction enzymes are larger class of enzymes called nucleases and they are of two types exonucleases and endonucleases.

Exonucleases remove nucleotides from the ends of the DNA whereas endonucleases makes cuts at specific positions within the DNA.

(b) Restriction endonuclease functions by ‘inspecting’ the length of a DNA Sequence and once it recognises the sequence, it will bind with the DNA and cut each of the two strands of the double helix at specific points in their sugar-phosphate backbones.

Each restriction endonuclease recognises a specific nucleotide sequences in the DNA. Restriction enzymes cut the strand of DNA away from the centre of the palindrome sites but between the same two bases on the opposite strands.

This leaves single stranded portions at the ends and there are overhanging stretches called sticky ends on each strand. These are named so because they form hydrogen bonds with their complementary cut. This stickiness of the ends facilitates the action of the enzyme DNA ligase. Restriction endonucleases are used in genetic engineering for formation of ‘recombinant’ molecules of DNA, which are composed of DNA from different sources or genomes.

Diagrammatic representation of steps involved in the formation of recombinant DNA by action of restriction endonuclease:

Note
Palindrome is group of letters that forms the same words when read both forward and backward, e.g., ‘MALAYAM’.

Question 16.
Name any two sources of e-Wastes and write two different ways for their disposal.
Answer:
Irreparable computers and other electronic goods such as mobile phones are two sources of electronic wastes (e-wastes).
The e-wastes are buried in landfills or incinerated.

Question 17.
Why the pyramid of energy is always upright ? Explain.
Answer:
The pyramid of energy is always upright because the energy flow in a food chain is always unidirectional and also with every increasing trophic level, some amount of energy is lost into the environment and never goes back to the sun.
Diagrammatic Representation of Pyramid of energy:

Note
The pyramid of energy represents that primary producers convert only 1% of the ene’ in the sunlight available to them into NPP.

Question 18.
Explain why very small animals are rarely found bipolar region.
Answer:
Small animals have a larger surface area relative their volume and they tends to lose body heat fast when it is cold outside. They have to expand much energy for generation of body heat through metabolism and this is reason that small animals are rarely found in the polar regions.

Section – C

Question 19.
Draw a diagram of the microscopic structure of human sperm. Label the following parts in it and write their functions.
(a) Acrosome
(b) Nucleus
(c) Middle piece
Answer:
Diagrammatic representation of human sperm:

(a) Acrosome: The anterior portion of sperm head contains an elongated haploid nucleus and is covered
by a cap-like structure called acrosome. It is filled with enzymes that help in fertilisation of the ovum.

Note
The acrosome contains hyaluronidase enzyme that breaks the outer membrane called zona pellucida layer of the ovum and allows the haploid nucleus of the sperm to fuse with the haploid nucleus in the ovum.

Note
The acrusome contains hyaluronidaxe enzyme that breaks the outer membrane called zona pellucida layer of the ovum and allows the haplold nucleus of the sperm to fuse with the haploid nucleus in the ovum.

(b) Nucleus: The nucleus of the sperm cell contains the genetic material such as DNA and during the process of fertilisation; the haploid nucleus of the sperm tends to fuse with haploid nucleus of the egg to form a diploid zygote.

(c) Middle piece: The middle piece possesses numerous mitochondria, which produces energy for the movement of tail that facilitates sperm motility which is essential for fertilisation.

Question 20.
With the help of any two suitable examples explain the effect of anthropogenic actions on organic evolution.
Answer:
The effect of anthropogenic actions on organic evolution:

(i) Industrial melanism: Before industrialization, it was observed that there were more white-winged moths or melanised moths were found on the trees than dark-winged moths. But after industrialization in 1920s, it was observed that there were more dark-winged moths were found in the same area. It occurs because during post-industrialisation period, the tree trunks became dark due to industrial smoke and soots. In this condition, the white-winged moth did not survive because of predators. Hence dark-winged or melanised moth survived.

(ii) Use of herbicides and pesticides results in the selection of resistant varieties in very short time scale. It also leads to the development of microbes resistant to several antibiotics in a shorter time period because of anthropogenic actions.

Question 21.
(a) Why is human ABO blood group gene considered a good example of multiple alleles ?
(b) Work out a cross up to Fj generation only, between a mother with blood group A (Homozygous) and the father with blood group B (Homozygous). Explain the pattern of inheritance exhibited.
Answer:
(a) The inheritance of human blood group is an example of codominance and multiple alleles. ABO blood grouping in human beings are controlled by I gene. The plasma membrane of the red blood cells has sugar polymers that are found on the surface of RBCs and is controlled by this gene.

The I gene has three alleles I ^A , I ^B and i. The gene I ^A and I ^B are dominant over i and both I ^A and I ^B express their own types of sugars. This phenomenon is called Codominance. Hence, red blood cells have both A and B types of sugars. While i allele do not produce any sugar. There are three different alleles and there are six different genotypes of the human ABO blood types.

Tabular representation of genetic basis of Blood Groups in Human population:

(b) Genetic Cross:

The above cross indicates that, if the mother has A blood group (homozygous) and father has B blood group (homozygous) conditions, then, all the offsprings will have AB blood group.

Question 22.
Describe the structure of a RNA polynucleotide chain having four different types of nucleotides.
Answer:
RNA (Ribonucleic acid) is a single stranded nucleic acid. It is a polymer of ribonucleotides that contains four nitrogenous bases such as adenine, guanine, uracil and cytosine.
Nucleoside = Nitrogenous base + Pentose sugar -ribose sugar (linked by N-glycosidic bond)
Nucleotide = Nucleoside + phosphate group (linked by phosphodiester bond)

Nucleotides are linked together by 3’-5’ phosphodiester bond for the formation of polynucleotide chain of RNA.
In a polynucleotide chain, a phosphate moiety remains free at 5 ’ end of ribose sugar (5 ’ end of polymer chain) and one -OH group remains free at 3’ end of ribose (3’ end of polymer chain).

Diagrammatic representation of RNA polynucleotide:

Note
RNA is unstable because of the presence of 2 ‘-OH group at second position in ribonucleotide as well as the presence of uracil in place of thymine.

Question 23.
Differentiate between inbreeding and outbreeding in cattle. State one advantage and one disadvantage for each one of them.
Answer:
Inbreeding: Inbreeding refers to the mating of more closely related individuals within the same breed for 4-6 generations.

Reduced fertility and productivity in a herd of cattle is because of inbreeding depression. Inbreeding depression occurs because of inbreeding. This problem can be overcome by mating of selected animals with the unrelated superior animals of the same breed. This helps to restore the fertility and productivity.

Disadvantage of inbreeding is inbreeding depression. Inbreeding reduces fertility and productivity of an animal.

Advantage of inbreeding increases homozygosity as inbreeding helps in the development of pureline in any animal.

It can be overcome by using different technique such as:

Outbreeding in which breeding of the unrelated animals that may be between individuals of the same breed but no common ancestors or between different breeds (crossbreeding) or different species (inter-specific hybridisation).

Advantages of outbreeding is that it produces hybrids with desirable characters such as better lactation period, high milk production and high-quality meat.

Disadvantage of outbreeding is that it causes outbreeding depression because of this there is decline in reproductive fitness.

Question 24.
(a) Why are the fruit juices bought from market clearer as compared to those made at home?
(b) Name the bioactive molecules produced by Trichoderma polysporum and Monascus purpureus.
Answer:
(a) The bottled juices that we have brought from the market are clearer as compared to those made at home because the bottled juices are clarified by the use of pectinases and proteases enzymes.

(b) Trichoderma polysporum is fungus that produces an bioactive molecule called cyclosporin A that is used as an immunosuppressive agents in organ-transplant patients.
Monascus purpureus is a yeast that produces statin which is used as a blood-cholesterol lowering agent.

Note
Statin acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.

Question 25.
(a) Why are transgenic animals so called ?
(b) Explain the role of transgenic animals in
(i) Vaccine safety and
(ii) Biological products with the help of an example each.
Answer:
(a) Animals that have had their DNA manipulated to possess and express a gene of interest are known as transgenic animals. Transgenic animals such as rats, rabbits, pigs, sheep, cows and fish have been produced.

(b) (i) Vaccine safety: Transgenic mice are being developed for use in testing the safety of vaccines before they are used on humans. Transgenic mice are being used for testing the safety of the polio vaccine.
(ii) Biological products: Medicines are required for treatment of certain human diseases that contains biological products but are expensive to make.

So, transgenic’animals that produce useful biological products can be created by the introduction of the portion of DNA (or genes) that codes for a particular product such as human protein called alpha-1 -antitrypsin) which is used for the treatment of emphysema.

Similarly, transgenic animals are used for the treatment of phenylketonuria (PKU) and cystic fibrosis. In 1997, the first transgenic cow, Rosie, produced human protein-enriched milk (2.4 grams per litre). The milk contained the human alpha-lactalbumin and was nutritionally a more balanced product for human babies than natural cow-milk.

Question 26.
How have human activities caused desertification ? Explain.
OR
How does algal bloom destroy the quality of a fresh water body ? Explain.
Answer:
Human activities such as over-cultivation, unrestricted grazing, deforestation and poor irrigation practices results in arid patches of land. The open lands without any cover of vegetation are prone to soil erosion.

The eroded soil is insufficient in providing nutrition to the plants. The land becomes barren over the years and such large barren patches extend and also meet over time in order to form a desert. Rapid urbanisation is also responsible for desertification.

Note
Desertification is a type of land degradation in which biological productivity is lost due to natural processes or induced by Inman activities whereas fertile areas become increasingly more arid.

OR

Presence of large amount of nutrients in water promotes the excessive growth of planktonic or free-floating algae called algal bloom. It imparts a distinct colour to the water bodies and algal blood leads to cause deterioration of the water quality and fish mortality. Some bloom-forming algae are extremely toxic to human beings and animals.

Question 27.
Explain mutualism with the help of any two examples. How is it different from commensalism ?
Answer:
Mutualism is a type of population interaction that confers benefits on both the interacting species. For example: Lichens represent an intimate mutualistic relationship between a fungus and photosynthesising algae or cyanobacteria.

The Mycorrhizae are associations between fungus and the roots of higher plants. The fungus help the plant in the absorption of essential nutrients from the soil while the plant in turn provides the fungus with energy-yielding carbohydrates.

Commensalism is a type of population interaction in which one species benefits and other is neither harmed nor benefitted.

For example: An orchid growing as an epiphyte on a mango branch and barnacles growing on the back of a whale benefit while neither the mango tree not the whale derives any apparent benefit.

Section – D

Question 28.
(a) Draw a diagrammatic sectional view of a mature anatropous ovule and label the following parts in it:
(i) that develops into seed coat.
(ii) that develops into an embryo after fertilisation.
(iii) that develops into an endosperm in an albuminous seed.
(iv) through which the pollen tube gains entry into the embryo sac.
(v) that attaches the ovule to the placenta.
(b) Describe the characteristic features of wind pollinated flowers.

OR

(a) Draw a diagrammatic sectional view of the female reproductive system of human and label the parts
(i) where the secondary oocytes develop
(ii) which helps in collection of ovum after ovulation
(iii) where fertilisation occurs
(iv) where implantation of embryo occurs.
(b) Explain the role of pituitary and the ovarian hormones in menstrual cycle in human females.
Answer:
(a) Diagrammatic representation of a typical anatropous ovule:

(i) Integument
(ii) Embryo sac
(iii) Nucellus
(iv) Micropyle
(v) Funicle

(b) The characteristic features of wind-pollinated flowers are as follows:

• Pollen grains are light, dry and non-sticky.
• Flower produces a large number of pollen grains.
• Open flowers with well-exposed stamen so that pollen can easily be dispersed.
• Flowers have a large and feathery stigma.

OR

(a) Diagrammatic representation of section view of female reproductive system:

(i) Ovary
(ii) Fimbriae
(iii) Isthmus and ampulla junction
(iv) Endometrium (2 Marks)

(b) Changes that takes place in the ovary and uterus during menstrual cycle are caused because of the change in the levels of pituitary and ovarian hormones. After menstrual phase gonadrotropin hormone such as LH (luteinising hormone) and follicular stimulating hormone (FSH) are released from pituitary. Their level gradually increases during follicular phase and it stimulates the development of follicles and secretion of estrogen hormone by growing follicles. So, both LH and FSH attain peak on 13th and 14th day. Rapid secretion of LH causes ovulation on day 14.

During luteal phases, Graafian follicle changes into corpus luteum which secretes progesterone which plays an important role in the maintenance of endometrium that is necessary for implantation.

Question 29.
(a) Write the conclusion drawn by Griffith at the end of his experiment with Streptococcus pneumoniae.
(b) How did O. Avery, C MacLeod and M. McCarty prove that DNA was the genetic material? Explain.
OR
(a) Explain the mechanism of sex-determination in humans.
(b) Differentiate between male heterogamety and female heterogamety with the help of an example of each.
Answer:
(a) At the end of the experiment based on Streptococcus pneumoniae Griffith concluded that the transformation of R strain by the heat killed S strain indicated the presence of a transforming principle or genetic material. This transforming principle made the R strain virulent (2 Marks)

(b) They purified biochemicals (proteins, DNA, RNA, etc.) from the heat – killed S cells. They discovered that DNA alone from S bacteria caused R bacteria to become transformed. They also discovered that protein – digesting enzymes (proteases) and RNA – digesting enzymes (RNases) did not affect transformation, so the transforming substance was not a protein or RNA. Digestion with DNase did inhibited transformation, suggesting that the DNA caused the transformation. They concluded that DNA is the hereditary material. (3 Marks)

OR

(a) The mechanism of sex determination in humans is as follows :

• In human beings the mechanism of sex determination is influenced by inheritance of either XY or XX type of chromosomes.
• In humans, the nucleus of each cell comprise of 46 chromosomes or 23 pairs of chromosomes including 22 pairs of autosomes and one pair of sex chromosome.
• In females there are two homomorphic pairs of XX chromosomes are available.
• Males have two heteromorphic sex chromosomes, XY.
• Females are homogametic in nature, they produce only one type of egg (22 + X).
• Males are heterogametic in nature, they are able to produce two types of sperms (22 + X) and (22 + Y).
• During the process of fertilisation, if the sperm having X chromosome fertilises with the egg having X chromosome, then the resulting offspring will be female (XX).
• If the sperm having Y chromosome fuses with the egg having X chromosome, then the resulting offspring would be a male (XY).

(b)

Male Heterogamety	Female Heterogamety
(i) When a male parent produces two different gametes during sexual reproduction this is known as male heterogamety.	(i) When a female parent produces two different gametes during sexual reproduction this is known as female heterogamety.
(ii) Examples :- Human males producing XY sex gametes.	(ii) Female birds producing ZW sex gametes

Question 30.
A child suffering from Thalassemia is bom to a normal couple. But the mother is being blamed by the family for delivering a sick baby.
(a) What is Thalassemia?
(b) How would you counsel the family not to blame the mother for delivering a child suffering from this disease? Explain.
(c) List the values your counselling can propagate in the families.
Answer:
(a) Thalassemia is an autosomal recessive disorder. It is caused due to the mutation or deletion of gene that controls the formation of globin chain of haemoglobin. This results in anaemia.

(b) Thalassemia is an autosomal recessive disorder as in this disorder the mutation is carried on one of the autosomes, so the carrier can be any one of the two parents and has an equal probability for coming from both mother and father. So, to just blame the mother for the child’s abnormality is unjustified.

(c) The following values can be given to the families such as:

• provide a healthy diet to the children
• accepting their child with all the positives and negatives
• neither of the parents are responsible for giving birth to a sick child
• the defect is caused because of a random change in the genes of the child
• provide emotional support to child to overcome his/her anxiety, depression and fear about the disorder.

Note
Thalassemia is a type of Mendelian disorder.