CBSE Class 12th Biology Practice Paper Set 1
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This practice paper is completely based on the CBSE class 12th Biology question paper 2012 in MCQ form to build you concept in class 12th biology
This practice paper can also be helpful for NEET (AIPMT)
For example:
Q. Why is it important to feed the newborn babies on colostrum?
The above given question could be asked in NEET in the following way:
Q. Read the important statement in favor of colostrums
i. It produces immunoglobulin and cytokines where IgA is in highest proportion
ii. It provides vitamins and essential oils but not minerals
iii. It transfer growth factor like epidermal and epithelial Read moregrowth factor
iv. It is nature’s perfect first food
Select the incorrect option
a) i, ii
b) i, iv
c) i, iii, iv
d) i, iii
Learn and judge yourself with jagranjosh. Com practice question paper that how question are being framed in CBSE class 12th board exam as well as in NEET
- 1.
Banana is considered a good example of parthenocarpy because
- A.
It produces seedless fruit in the absence of successful fertilization
- B.
It produces seedless fruit in the presence of successful fertilization
- C.
It produces seedless fruit in the absence of successful Ovulation
- D.
It produces leafless fruit in the absence of successful ovulation
Correct Answer
A. It produces seedless fruit in the absence of successful fertilizationExplanation
Banana is considered a good example of parthenocarpy because it produces seedless fruit in the absence of successful fertilization. Parthenocarpy is a phenomenon where fruits develop without the need for pollination or fertilization. In the case of bananas, the fruit develops from the ovary without the need for the ovules to be fertilized. This can occur naturally or can be induced through artificial means such as hormone treatments. The resulting fruit is seedless, as there was no fertilization to produce viable seeds.Rate this question:
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- 2.
Two different roles of spleen in the human body are
- A.
Inhibit the filtration process plus remanufacture damaged red blood cells
- B.
Control the breakdown of sugar and developing immunity against infection
- C.
Developing immunity that is protection against infection plus recognizes and removes old, malformed, or damaged red blood cells
- D.
All of the above are the function of spleen
Correct Answer
C. Developing immunity that is protection against infection plus recognizes and removes old, malformed, or damaged red blood cellsExplanation
The correct answer is "Developing immunity that is protection against infection plus recognizes and removes old, malformed, or damaged red blood cells". The spleen plays a crucial role in the immune system by producing and storing immune cells, such as lymphocytes, which help fight against infections. Additionally, the spleen acts as a filter, removing old, malformed, or damaged red blood cells from circulation. Therefore, this answer accurately describes the two different roles of the spleen in the human body.Rate this question:
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- 3.
A garden pea plant produced axial white flowers. Another of the same species produced terminal violet flowers. Identify the dominant traits.
- A.
White and green
- B.
Red and green
- C.
White and purple
- D.
Pink yellow
Correct Answer
C. White and purpleExplanation
The dominant traits in this scenario are white and purple flowers. This is because one of the garden pea plants produced axial white flowers, indicating that the white flower trait is dominant. Additionally, another plant of the same species produced terminal violet flowers, indicating that the purple flower trait is also dominant.Rate this question:
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- 4.
It is desirable to use unleaded petrol in vehicles fitted with catalytic converters. Select the correct option for the main function of catalytic convertor?
- A.
Reduce the emission of CFC
- B.
To get the good efficiency of the engine
- C.
Stop the emission of other dangerous compounds
- D.
Reduce the emission of other dangerous compounds
Correct Answer
D. Reduce the emission of other dangerous compoundsExplanation
The main function of a catalytic converter is to reduce the emission of other dangerous compounds. This is achieved by converting harmful pollutants in the exhaust gases into less harmful substances through a series of chemical reactions. Unleaded petrol is desirable because it does not contain lead, which can damage the catalytic converter and reduce its effectiveness in reducing emissions.Rate this question:
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- 5.
Identify the location and function of acrosome in human body
- A.
In the head part of the sperm, provide mobility to the sperm and to promote meiosis following fertilization
- B.
In the middle part of the sperm, provide mobility to the sperm and to inhibit meiosis following fertilization
- C.
In the middle part of the chromosome, facilitate linkage during meiosis following fertilization
- D.
In the head part of the sperm ,stores powerful enzymes needed to avoid the egg (zona pellucida)
Correct Answer
A. In the head part of the sperm, provide mobility to the sperm and to promote meiosis following fertilizationExplanation
The acrosome is located in the head part of the sperm and its function is to provide mobility to the sperm and to promote meiosis following fertilization. Meiosis is a crucial process that leads to the formation of gametes, such as sperm and eggs. The acrosome contains powerful enzymes that are needed for the sperm to penetrate and fertilize the egg by breaking down the protective layer called the zona pellucida. Therefore, the acrosome plays a vital role in the reproductive process by enabling the sperm to reach and fertilize the egg.Rate this question:
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- 6.
Select the name of most common species of bees suitable for apiculture
- A.
Apis indica
- B.
Apis florae
- C.
Apis mellifera
- D.
Apis dorsat
Correct Answer
A. Apis indicaExplanation
The correct answer is Apis mellifera. This is the most common species of bees used in apiculture, also known as honey bee. Apis indica is not a commonly used species for apiculture.Rate this question:
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- 7.
Write the name of an improved breed of chicken
- A.
Leghorn
- B.
Rhode Island Red
- C.
Ancona and Minorca
- D.
Light Sussex
Correct Answer
B. Rhode Island RedExplanation
Rhode Island Red is a breed of chicken that is known for its hardiness, versatility, and ability to lay a good number of brown eggs. It is a popular breed among backyard chicken keepers and small-scale farmers due to its excellent meat quality and ability to thrive in various climates. Rhode Island Reds are also known for their calm and friendly temperament, making them a great choice for families and beginners in chicken keeping.Rate this question:
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- 8.
Comment on the similarity between the wing of a cockroach and the wing of a bird. What do you infer from the above, with reference to evolution?
- A.
Basically they are analogous as differ in origin and functionally similar
- B.
Basically they are analogous as differ in function and similar in origin
- C.
Basically they are homologous as differ in origin and functionally similar
- D.
All are correct in reference of evolution
Correct Answer
A. Basically they are analogous as differ in origin and functionally similarExplanation
The explanation for the given correct answer is that the wings of a cockroach and a bird are analogous because they have different origins (they evolved independently) but are functionally similar (both are used for flying). This suggests that evolution has led to the development of similar structures in different organisms to perform similar functions, even though they may have different origins.Rate this question:
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- 9.
Choose the correct option in reference to the role of cyanobacteria as a biofertiliser
- A.
They add inorganic matter to the soil and help in decreasing its fertility
- B.
They add organic matter to the soil and to help in decreasing its fertility
- C.
They add organic matter to the soil and to help in increasing its fertility
- D.
They utilize organic matter to the soil and to help in increasing the porosity of the soil
Correct Answer
C. They add organic matter to the soil and to help in increasing its fertilityExplanation
Cyanobacteria are known to be biofertilizers because they have the ability to fix atmospheric nitrogen into a usable form for plants. This process helps in increasing the fertility of the soil by providing a nutrient source for plants. Additionally, cyanobacteria also add organic matter to the soil through their growth and decomposition, further enhancing soil fertility. Therefore, the correct option is "They add organic matter to the soil and help in increasing its fertility."Rate this question:
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- 10.
Given is the structure of nucleosome Choose the correct reason which enables histones to acquire a positive charge
- A.
Presence of histidine and aspartic acid which are positively charged in their side chains
- B.
Presence of lysine and arginine which are positively charged in their side chains
- C.
Presence of lysine and aspartic acid which are positively charged in their side chains
- D.
Presence of glutamic acid and aspartic acid which are positively charged in their side chains
Correct Answer
B. Presence of lysine and arginine which are positively charged in their side chainsExplanation
Lysine and arginine are both amino acids that contain positively charged side chains. These positive charges on the side chains of lysine and arginine enable histones to acquire a positive charge. This positive charge allows histones to interact with and bind to the negatively charged DNA molecule, forming the nucleosome structure.Rate this question:
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- 11.
Select the correct statement regarding cleistogamy
- A.
It produces assured seed set only in the presence of pollinators
- B.
It will lead to a strong progeny
- C.
It produce a flower that are variably autogamus
- D.
It produces assured seed set even in the absence of pollinators
Correct Answer
D. It produces assured seed set even in the absence of pollinatorsExplanation
Cleistogamy is a type of self-pollination in plants where the flowers remain closed and do not require external pollinators for fertilization. This allows for the production of seeds even in the absence of pollinators. Therefore, the statement that "It produces assured seed set even in the absence of pollinators" is correct.Rate this question:
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- 12.
Read the important statement in favor of colostrums i. It produces immunoglobulin and cytokines where IgA is in highest proportion ii. It provides vitamins and essential oils but not minerals iii. It transfer growth factor like epidermal and epithelial growth factor iv. It is nature’s perfect first food Select the incorrect option
- A.
I, ii
- B.
I, iv
- C.
I, iii, iv
- D.
I, iii
Correct Answer
A. I, iiExplanation
The incorrect option is i, ii. This is because colostrum does not provide minerals, but it does produce immunoglobulin and cytokines, with IgA being in the highest proportion. Additionally, colostrum transfers growth factors like epidermal and epithelial growth factor, making it nature's perfect first food.Rate this question:
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- 13.
Choose the correct option for β-Galactosidese
- A.
It is coded by “z” genes and responsible for the hydrolysis of lactose into galactose and glucose
- B.
It is coded by “y” gene and responsible to increase the permeability of cell
- C.
It is coded by “i” genes and responsible for the hydrolysis of lactose into galactose and glucose
- D.
The main function of β-Galactosidese is to have an overall control on the functioning of all genes
Correct Answer
A. It is coded by “z” genes and responsible for the hydrolysis of lactose into galactose and glucoseExplanation
The correct answer is that β-Galactosidese is coded by "z" genes and is responsible for the hydrolysis of lactose into galactose and glucose. This enzyme plays a crucial role in lactose metabolism by breaking down lactose, a disaccharide, into its monosaccharide components. The "z" genes encode for the synthesis of β-Galactosidese, which is essential for the utilization of lactose as a carbon source by the cell.Rate this question:
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- 14.
Read all the statements about human testes i. It is present in a pouch which helps to maintain the lower temperature of testes required for spermatogenesis ii. Each testes has about 500 compartments called seminiferous tubules iii. Testes has leydig cells to synthesis and secrete androgen hormone iv. In adults, each testes is circular shape Select the correct statement from above
- A.
I, ii
- B.
I, iii
- C.
Iii, iv and i
- D.
I, iv
Correct Answer
B. I, iiiExplanation
The correct answer is "i, iii".
Statement i states that the testes are present in a pouch which helps to maintain the lower temperature required for spermatogenesis. This is true because the testes need to be kept at a slightly lower temperature than the rest of the body for the production of sperm.
Statement iii states that the testes have Leydig cells which synthesize and secrete androgen hormones. This is also true because Leydig cells are responsible for producing testosterone, which is an androgen hormone.
Therefore, the correct answer is "i, iii" because both statements are true.Rate this question:
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- 15.
Parthenogenesis means
- A.
Production of complete individual from unfertilized egg
- B.
Production of incomplete individual from unfertilized egg
- C.
Production of fruit from unfertilized ovule
- D.
Production of incomplete flower from unfertilized ovule
Correct Answer
A. Production of complete individual from unfertilized eggExplanation
Parthenogenesis refers to the process of producing a complete individual from an unfertilized egg. In this reproductive strategy, the egg develops and grows without being fertilized by sperm. This phenomenon is observed in certain species, such as some insects, reptiles, and fish. It allows for the production of offspring without the need for a male partner and can be advantageous in certain environments or situations where males are scarce or absent.Rate this question:
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- 16.
Name the plant source of ganja. How does it affect the body of the abuser?
- A.
Leaves and the raisin of cannabis plant and it directly affects the respiratory system
- B.
Leaves and the raisin of Atropa belladona and it directly affects the cardiovascular system
- C.
Leaves and the raisin of Atropa belladona and it directly affects the cardiovascular system
- D.
Leaves and the raisin of cannabis plant and it directly affects the cardiovascular system
Correct Answer
D. Leaves and the raisin of cannabis plant and it directly affects the cardiovascular systemExplanation
The correct answer is "leaves and the raisin of cannabis plant and it directly affects the cardiovascular system." Ganja, also known as marijuana, is derived from the cannabis plant. When consumed, it can have various effects on the body, including an increased heart rate and blood pressure, which directly affects the cardiovascular system.Rate this question:
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- 17.
Identify the cause and the body system affected by ADA deficiency in humans.
- A.
Deletion of gene for ADA which effects the functioning of immune system
- B.
Substitution of gene for ADA which effects the functioning of immune system
- C.
Deletion of gene for ADA which effects the functioning of pancreatic glands
- D.
Addition of gene for ADA which effects the functioning of immune system
Correct Answer
A. Deletion of gene for ADA which effects the functioning of immune systemExplanation
ADA deficiency in humans is caused by the deletion of the gene for ADA, which affects the functioning of the immune system. ADA (adenosine deaminase) is an enzyme that plays a crucial role in the development and maturation of immune cells. Without ADA, toxic metabolites accumulate in the body, leading to severe combined immunodeficiency (SCID). SCID is a disorder characterized by a weakened immune system, making individuals highly susceptible to infections. Therefore, the deletion of the ADA gene directly affects the functioning of the immune system.Rate this question:
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- 18.
Bacterium that causes typhoid and mention one diagnostic symptoms
- A.
Retrovirus and sustained high fever
- B.
Salmonella typhi and sustained high fever
- C.
Salmonella typhoid and loss of Visuality
- D.
Clostridium tetani and temporary paralysis
Correct Answer
B. Salmonella typhi and sustained high feverExplanation
Salmonella typhi is the bacterium that causes typhoid fever. One of the diagnostic symptoms of typhoid fever is a sustained high fever. This means that the person affected by the disease will have a fever that lasts for a prolonged period of time without any significant fluctuations. Therefore, the correct answer is Salmonella typhi and sustained high fever.Rate this question:
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- 19.
In humans, the dominance relationship between the A and B alleles of the ABO blood group gene is an example of
- A.
Complete dominance
- B.
Incomplete dominance
- C.
Codominance
- D.
Epistasis
Correct Answer
C. CodominanceExplanation
Codominance is the correct answer because in the ABO blood group gene, both the A and B alleles are expressed equally and simultaneously in individuals who inherit both alleles. This means that both the A and B antigens are present on the surface of red blood cells, resulting in the AB blood type. This is different from complete dominance, where one allele is completely dominant over the other, and incomplete dominance, where a blend of the two alleles is observed. Epistasis refers to the interaction between different genes, which is not applicable in this case.Rate this question:
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- 20.
Select the incorrect statement which does not support the Darwin’s theory of Natural Selection
- A.
Members of a population do not have a heritable variations
- B.
In a population, more individuals are produced each generations that can survive or reproduce
- C.
The result of natural selection is a population adapted to it
- D.
Some individuals have adaptive characteristics that enable them to survive and reproduce better than other individuals
Correct Answer
A. Members of a population do not have a heritable variationsExplanation
This statement is incorrect because Darwin's theory of natural selection is based on the idea that individuals in a population do have heritable variations. These variations are passed on from one generation to the next through genes, and they provide the raw material for natural selection to act upon. Without heritable variations, there would be no genetic diversity in a population, and natural selection would not be able to drive the evolution of species.Rate this question:
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- 21.
The functions of umbilical cord is
- A.
It supplies oxygen to the foetus
- B.
It delivers nutrients to foetus
- C.
It helps to withdraw blood rich in carbon dioxide and depleted in nutrients
- D.
All the above are correct
Correct Answer
D. All the above are correctExplanation
The umbilical cord serves multiple functions during pregnancy. It supplies oxygen to the fetus, ensuring its proper development. It also delivers essential nutrients to the fetus, which are necessary for its growth. Additionally, the umbilical cord helps to withdraw blood that is rich in carbon dioxide and depleted in nutrients from the fetus, keeping it healthy. Therefore, all the given statements about the functions of the umbilical cord are correct.Rate this question:
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- 22.
Why are DNA polymerases from thermophilic organisms used in the polymerase chain reaction?
- A.
Because they are required to keep the two strands separated
- B.
Because they cannot add new nucleotides at low temperatures
- C.
Because they are easier to isolate than psychrophilic DNA polymerases
- D.
Because the priming and extension steps must be carried out at high temperatures to prevent the single strands from reannealing
Correct Answer
D. Because the priming and extension steps must be carried out at high temperatures to prevent the single strands from reannealingExplanation
DNA polymerases from thermophilic organisms are used in the polymerase chain reaction (PCR) because the priming and extension steps of PCR must be carried out at high temperatures to prevent the single strands of DNA from reannealing. Thermophilic DNA polymerases are able to function at these high temperatures, allowing for efficient and accurate DNA amplification during PCR.Rate this question:
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- 23.
Blood test in malaria should be done
- A.
When temperature is low
- B.
During evening when temperature is very low
- C.
When temperature is high
- D.
During night only
Correct Answer
C. When temperature is highExplanation
Blood tests for malaria should be done when the temperature is high because the malaria parasite, Plasmodium, is more active and replicates faster in warmer temperatures. This increases the chances of detecting the presence of the parasite in the blood sample. Additionally, high temperatures are often associated with fever, which is a common symptom of malaria. Therefore, conducting blood tests when the temperature is high increases the accuracy of diagnosing malaria.Rate this question:
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- 24.
An insect becomes resistant to parasite is an example of
- A.
Artificial selection
- B.
Mercy killing
- C.
Origin of species
- D.
Natural selection
Correct Answer
D. Natural selectionExplanation
Natural selection is the process by which organisms with advantageous traits are more likely to survive and reproduce, leading to the passing on of those traits to future generations. In this scenario, the insect becoming resistant to a parasite is a result of natural selection. The insects that have a genetic variation that makes them resistant to the parasite are more likely to survive and reproduce, passing on this resistance to their offspring. Over time, the population of insects will become predominantly resistant to the parasite due to the selective pressure exerted by the parasite.Rate this question:
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- 25.
Choose the correct salient features / features of double helix structure of DNA
- A.
It is made of two polynucleotide chains, where the backbone is constituted by sugar-phosphate and the bases project inside
- B.
The pitch of the helix is 3.4nm and there are roughly 10 bp in each turn
- C.
Two nucleotides are linked through phosphodiester bond
- D.
All of the above are correct
Correct Answer
D. All of the above are correctExplanation
The given answer is correct because all of the provided statements accurately describe the salient features of the double helix structure of DNA. The first statement mentions that the structure is composed of two polynucleotide chains with a sugar-phosphate backbone and bases projecting inside. The second statement states that the pitch of the helix is 3.4nm and there are approximately 10 base pairs in each turn. The third statement correctly states that nucleotides are linked together through phosphodiester bonds. Therefore, all of the above statements are true and describe the features of the double helix structure of DNA.Rate this question:
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- 26.
BOD is ______ in polluted water and ______ in potable water.
- A.
More, less
- B.
Less, medium
- C.
Medium, more
- D.
Less, more
Correct Answer
A. More, lessExplanation
BOD (Biochemical Oxygen Demand) is a measure of the amount of oxygen required by microorganisms to decompose organic matter in water. In polluted water, there is a higher concentration of organic pollutants, which leads to an increased demand for oxygen by microorganisms. Therefore, BOD is more in polluted water. On the other hand, potable water is treated to remove organic pollutants, resulting in a lower concentration of organic matter and a lower demand for oxygen. Hence, BOD is less in potable water.Rate this question:
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- 27.
When the secondary oocyte is released from the ovary, it is surrounded by
- A.
Corpus luteum
- B.
Zona pellucid
- C.
Corona radiate
- D.
B & c only
Correct Answer
D. B & c onlyExplanation
The secondary oocyte is surrounded by two structures when it is released from the ovary: the zona pellucida and the corona radiata. The zona pellucida is a glycoprotein layer that surrounds the oocyte and plays a crucial role in fertilization. The corona radiata, on the other hand, is a layer of granulosa cells that surround the oocyte and provide protection and nourishment. Therefore, the correct answer is "b & c only".Rate this question:
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- 28.
Column ‘M’ contains terms and column ‘N’ contains definitions. Match them correctly and choose the right answer. Column ‘M’ Column ‘N’ A. Parturition p. Attachment of zygote to endometrium B. Gestation q. Release of egg from Graafian follicle C. Ovulation r. Delivery of baby from uterus D. Implantation s. Duration between pregnancy and birth E. Conception t. Formation of zygote by fusion of the egg and Stoppage of ovulation and menstruation sperm
- A.
A = q, B = s, C = p, D = t, E = r
- B.
A = s, B = r, C = p, D = t, E = q
- C.
A = t, B = p, C = q, D = r, E = s
- D.
A = r, B = s, C = q, D = p, E = t
Correct Answer
D. A = r, B = s, C = q, D = p, E = t -
- 29.
A molecule that can act as a genetic material must fulfill some criteria. Read the following criteria and select the correct one from the given options i. It should be chemically and structurally be stable ii. It should not be able to express itself in the form of “Mendelian Characters iii. It should not provide the scope for mutation iv. It should be able to generate it’s replica
- A.
I, ii
- B.
I, iv
- C.
Iii, iv and i
- D.
I, iii
Correct Answer
B. I, ivExplanation
A molecule that can act as a genetic material must be chemically and structurally stable to ensure that it can carry and transmit genetic information accurately. Additionally, it should be able to generate its replica through processes like DNA replication. Therefore, the correct answer is i, iv.Rate this question:
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- 30.
Cause of seed coat rupture during seed germination is
- A.
Massive imbibitions of water
- B.
Sudden increase in cell division
- C.
Massive glycolysis in epidermis
- D.
Differentiation of cotyledon
Correct Answer
A. Massive imbibitions of waterExplanation
During seed germination, the seed coat needs to rupture for the embryo to emerge. This rupture is caused by the massive imbibition of water by the seed. When water is absorbed, it causes the seed to swell and the pressure exerted by the swelling seed leads to the rupture of the seed coat. This allows the embryo to grow and develop into a new plant.Rate this question:
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