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The correct answer is (a) MITOSIS

The best explanation: Mitosis results in the equal DIVISION of the chromosomal CONTENT of the cell. Hence it is also called equational division. The mitosis results in the production of two daughter CELLS from one parent cell with the exact chromosomal content as in the parent cell. This is ensured by a duplication event in the synthesis PHASE prior to the mitosis phase.

The correct answer is (a) True

Explanation: Genes are PRESENT on chromosomes. Each DIPLOID cell has a set of TWO chromosomes. Thus, genes also occur in pairs. The pair of genes are called alleles if they code for a different protein. Usually, one copy of gene is enough to code for a functional protein. Hence the other copy is kept silent. This results in the dominant and recessive nature of the genes.

The correct option is (a) REDISCOVERY of his work

To elaborate: These three scientists helped in the rediscovery of MENDEL’s work in the 1900S. Mendel’s work was published in 1865 and long forgotten.

Correct answer is (c) Sutton and BOVERI

For explanation: Sutton and Boveri, along with other scientists, had uncovered the complete movement of chromosomes during the PROCESS of CELL division. They observed that these MOVEMENTS correlate with Mendel’s FINDINGS.

Right option is (a) CHROMOSOMES

Easy explanation: Chromosomes means colored bodies/objects. The staining procedures ALLOWED biologists to visualize the nucleus and chromosomes during the PROCESS of CELL division.

Correct OPTION is (b) cell DIVISION

Explanation: Microscopy came into the PICTURE around the 1900S. This allowed SCIENTISTS to visualize cells and processes like cell division.

The CORRECT answer is (c) inability to isolate factors

For explanation I would SAY: Mendel’s WORK SUGGESTED the existence of stable and discrete factors. This was completely shocking for the contemporary scientific world. A major drawback that lied was the inability to DISCOVER the factors and prove their existence.

The correct OPTION is (d) Putin

Explanation: Mendel’s work was laid in PAPERS before people could recognize it after 1900. This was ACHIEVED by the rediscovery of his work by three scientists: DE VRIES, Correns, and Tschermark.

Right answer is (a) Mathematics to STUDY biological phenomena

To explain: People had performed CROSSES on garden pea PLANTS before MENDEL. But no one had applied a statistical and PROBABILISTIC approach to unveil the underlying phenomena. Mendel was the first to do so.

Right ANSWER is (a) CONTINUOUS

The best EXPLANATION: The variation observed in nature is mostly continuous. This arises from the complex GENETIC interactions which Mendel failed to observed in his EXPERIMENTS on pea plants.

The correct option is (B) Mendel’s factors were discrete, but natural changes blended

The best I can explain: Mendel’s LAWS of inheritance were based on the assumptions of factors/genes being discrete. However, most of the changes OBSERVED in nature exhibited the BLENDING of CHARACTERS. This led to the unacceptance of Mendel’s studies.

Correct option is (C) lack of the availability of efficient communication METHODS

To elaborate: MENDEL had published his work back in 1865. The communication methods were not well developed and for PEOPLE to recognize the importance of his work took more than half a decade after it had been published.

Right choice is (a) 2^N

The explanation is: In a POLY hybrid cross, each F1 is a heterozygote. According to the independent law of assortment, each gamete will get ONE copy of all N factors. Thus, there are 2^N types of gametes possible.

Correct answer is (a) True

To explain: For a DIHYBRID CROSS, four TYPES of gametes are PRODUCED by the heterozygotic generation. This gives rise to 4*4=16 combinations. HENCE 16 squares are required in the Punnett square.

Correct choice is (C) 2^(2N)

To explain: For a poly hybrid cross involving N traits, ACCORDING to the law of independent ASSORTMENT, 2^N types of gametes will be PRODUCED by each parent. Therefore, the cross of these PROGENY will give (2^N)*(2^N) = 2^(2N).

Right answer is (C) Yt, yt, YT, yT

To ELABORATE: TtYy is a DIHYBRID heterozygote. The independent LAW of assortment applies to it. Thus, it will produce four types of gametes. These will be TY, Ty, tY, and ty.

The correct CHOICE is (a) True

Best explanation: The law of INDEPENDENT assortment states that the segregation of traits is independent of ONE another in a dihybrid cross. THUS, a HETEROZYGOTE AaBb will produce four types of gametes: AB, Ab, aB, and ab.

The correct ANSWER is (a) xy

The explanation: For a dihybrid cross involving two traits, the independent LAW of assortment states that the traits would SEGREGATE independently of each other. THUS, the phenotypic ratio would be xy.

Correct answer is (c) For MULTIPLE traits under consideration, each SEGREGATE INDEPENDENTLY of one another

Best explanation: The law of independent assortment was the third law of Mendel. It states that when multiple traits are under consideration, each TRAIT SEGREGATES independently of the other.

The correct CHOICE is (d) Law of Independent Assortment

Easy explanation: The FIRST TWO laws of Mendel were based on his studies on MONOHYBRID crosses. These were the law of dominance and the law of segregation. The DIHYBRID cross studies supported them, but also led to the formulation of a third law: the law of independent assortment.

Correct answer is (a) 900 round yellow, 300 round GREEN, 300 wrinkled yellow and 100 wrinkled green

The best I can explain: The F2 PROGENY of a dihybrid Mendelian cross has a phenotypic ratio of 9:3:3:1. Thus of the 1600 plants sampled, 900 will be round yellow, 300 round green, 300 wrinkled yellow and 100 wrinkled green

Right ANSWER is (d) 9:3:3:1

For explanation I would say: The F2 generation in a DIHYBRID cross produces all possible phenotypes. The RATIO obtained for it is 9:3:3:1.

Correct option is (B) False

For explanation I would say: Mendel used the monohybrid cross to arrive at the laws of DOMINANCE and segregation. For the LAW of independent assortment, he did the DIHYBRID CROSSES.

Correct answer is (a) monohybrid cross

The BEST explanation: A dihybrid cross is the one where the partners involved are similar except for two traits under CONSIDERATION. These were STUDIED for the first time USING true-breeding LINES by Mendel.

The CORRECT choice is (d) Yellow SEEDS were three times more ABUNDANT than green seeds

For EXPLANATION: The roundness and greenness of the seeds are encoded by different genes. According to the law of independent assortment, these two should segregate independently of each other. Thus in the F2 generation, green seeds: yellow seeds = 3:1, round seeds: wrinkled seeds = 3:1. From this, we can have, green seeds: wrinkled seeds = 3:1, green seeds: round seeds = 1:1, yellow seeds: round seeds = 1:3, yellow seeds: wrinkled seeds = 1:1.

Correct option is (a) ROUND GREEN seeds

To explain: Round seeds are dominant over WRINKLED seeds. Also, yellow seeds are dominant over the green seeds. Thus, the progeny of these parents will be heterozygotic RESULTING expression of only the dominant CHARACTERS.

Correct OPTION is (C) Wrinkled round seeds

Easiest explanation: In the F2 generation of a dihybrid cross, all possible phenotypes are observed. Wrinkled and round are encoded by the same locus. HENCE, they cannot occur TOGETHER.

Right choice is (B) Heterozygosity

Explanation: The F1 progeny of a dihybrid cross are formed by a cross between parents that are homozygous for two traits. Thus, they are all HETEROZYGOUS.

Correct option is (d) AaBb

To EXPLAIN I would SAY: AABB parent will only be able to produce AB GAMETES, and aabb parent will only be able to produce ab gametes. THUS, the only possible GENOTYPE for the progeny is AaBb, a heterozygote.

Right answer is (b) RRYY and rryy

The explanation: The DIHYBRID cross is used to the inheritance pattern of two contrasting CHARACTERS. HENCE, they should be true-breeding. One for both dominant traits and the other for both recessive traits.

Right ANSWER is (a) Inflated green pods

Explanation: The F1 progeny will be HETEROZYGOTES. Hence the DOMINANT CHARACTERS will be expressed. THUS, all the F1 progeny will have inflated green pods.

Correct option is (a) IAIA, IAIB

The best explanation: The blood group O is ENCODED by ii. Thus, of the given options, only IAIA, IAIB parental pair cannot PRODUCE ii INFANTS.

Correct CHOICE is (a) A

The explanation is: The progeny has one COPY of IA and one copy of i. IA is dominant over i. THUS, only IA will be expressed. This will RESULT in A blood group.

Correct answer is (d) O

To elaborate: The only possible ALLELE that can be produced by IAIA parent is IA. Similarly, the only possible allele that can be produced by IBIB parent is IB. The PROGENY produced will have the alleles IA and IB. THUS, their blood group will be AB.

Correct OPTION is (d) O

To explain: The present of ii as the genotype RESULTS in no sugar antigen being EXPRESSED by the RBC. Thus, the blood group of the progeny is O.

Correct answer is (d) POPULATION

The best explanation: An individual can have a maximum of TWO alleles. Hence to STUDY MULTIPLE allelism, it is ESSENTIAL to sample a large chunk of the population.

The correct answer is (C) PHENOTYPE

To explain: The mode of INHERITANCE depends on the phenotype. A SINGLE gene can give rise to different phenotypes, with each phenotype showing a different mode of inheritance.

The CORRECT choice is (B) False

The BEST I can explain: The ABO system has THREE alleles IA, IB, and i. The number of phenotypes produced by these alleles is only three.

Right OPTION is (d) O

The best I can explain: The progeny of these PARENTS can have IAIA, IAIB, IAi, and IBi. Thus, the progeny can have either A, B, or AB BLOOD groups. The progeny with O blood group will be the only case that can be solved SIMPLY based on blood groups.

The correct option is (d) IC

Easy EXPLANATION: The gene I has only THREE alleles. These are IA, IB, and i. There is no ALLELE as IC. ALSO, the alleles IA and IB are dominant over i as it does not PRODUCE any sugar.