NEET Principles of Inheritance and Variation PYQ practice sheet

20 previous-year NEET Botany questions from Principles of Inheritance and Variation, newest papers first. Principles of Inheritance and Variation carries 36 of the Botany questions in NEET 2020 to 2026, so this is a good place to test yourself after revising the chapter. Marking: +4 correct, −1 wrong.

Practise all 31 online

1.
RE-NEET 2026
Given below are two statements : Statement I : Down's syndrome is caused by the absence of one of the X-chromosomes. Statement II : Turner's syndrome is caused by the presence of an additional copy of the chromosomes. In the light of the above statements, choose the correct answer from the options given below :
- (A)
  Both Statement I and Statement II are correct
- (B)
  Both Statement I and Statement II are incorrect
- (C)
  Statement I is correct but Statement II is incorrect
- (D)
  Statement I is incorrect but Statement II is correct
2.
RE-NEET 2026
For a person with blood group 'O', which of the following is not a possible combination of parents' blood group genotypes?
- (A)
  Father : $I^Bi$ and Mother : $I^Bi$
- (B)
  Father : $I^AI^B$ and Mother : $I^Ai$
- (C)
  Father : $I^Ai$ and Mother : $I^Ai$
- (D)
  Father : $I^Ai$ and Mother : $I^Bi$
3.
RE-NEET 2026
Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : In an experiment, Mendel observed that the F1 progeny plants are all tall and none are dwarf. Reason R : Stem height is a contrasting trait, with tall being dominant and dwarf being recessive. In the light of the above statements, choose the most appropriate answer from the options given below :
- (A)
  Both A and R are correct and R is the correct explanation of A
- (B)
  Both A and R are correct but R is not the correct explanation of A
- (C)
  A is correct but R is not correct
- (D)
  A is not correct but R is correct
4.
NEET 2026
Match List I with List II: List-I: A. Incomplete dominance, B. Co-dominance, C. Pleiotropy, D. Polygenic inheritance List-II: I. Human skin colour, II. Inheritance of flower colour in Antirrhinum sp., III. Phenylketonuria disease in humans, IV. ABO blood groups Choose the correct answer from the options given below:
- (A)
  A-II, B-I, C-III, D-IV
- (B)
  A-I, B-IV, C-III, D-II
- (C)
  A-I, B-III, C-II, D-IV
- (D)
  A-II, B-IV, C-III, D-I
5.
NEET 2026
Which of the following statements are true with reference to the sex-determination in honeybees? A. An offspring formed from the union of a sperm and an egg, develops as a female (queen or worker). B. An unfertilized egg develops as a male by parthenogenesis. C. A male has half the number of chromosomes than that of a female. D. Males produce sperms by meiosis. E. Honeybees have a haplodiploid sex-determination system. Choose the correct answer from the options given below:
- (A)
  A, B, C and D only
- (B)
  B, C, D and E only
- (C)
  A, B, C and E only
- (D)
  A, B, D and E only
6.
NEET 2026
Which one of the following disorders is caused by the substitution of Glutamic acid (Glu) by Valine (Val) at the sixth position of the beta globin chain of the haemoglobin molecule?
- (A)
  Phenylketonuria
- (B)
  Haemophilia
- (C)
  Thalassemia
- (D)
  Sickle-cell anaemia
7.
NEET 2026
What is the probability of having children with 'O' blood group, where both mother and father are heterozygous for 'A' and 'B' blood group, respectively?
- (A)
  75%
- (B)
  0%
- (C)
  25%
- (D)
  50%
8.
NEET 2026
The sixth mutant codon of beta globin gene causing polymerization of Haemoglobin and change in RBC shape is ______.
- (A)
  AUG
- (B)
  CAG
- (C)
  GAG
- (D)
  GUG
9.
NEET 2026
In a population of a grasshopper species, the chromosome number of some members is 23 and some other members possess 24 chromosomes. The 23 and 24 chromosome-bearing members in this species are ______.
- (A)
  males and females, respectively
- (B)
  all females
- (C)
  females and males, respectively
- (D)
  all males
10.
NEET 2026
In which animal do haploid cells divide mitotically to produce gametes?
- (A)
  Male earthworms
- (B)
  Male frogs
- (C)
  Male honeybees
- (D)
  Male grasshoppers
11.
NEET 2024
In a plant, black seed color (BB/Bb) is dominant over white seed color (bb). In order to find out the genotype of the black seed plant, with which of the following genotype will you cross it?
- (A)
  bb
- (B)
  BB/Bb
- (C)
  Bb
- (D)
  BB
12.
NEET 2024
A pink flowered Snapdragon plant was crossed with a red flowered Snapdragon plant. What type of phenotype/s is/are expected in the progeny?
- (A)
  Red flowered as well as pink flowered plants
- (B)
  Only red flowered plants
- (C)
  Only pink flowered plants
- (D)
  Red, Pink as well as white flowered plants
13.
NEET 2024
Match List I with List II. List I: A. Two or more alternative forms of a gene, B. Cross of $F_1$ progeny with homozygous recessive parent, C. Cross of $F_1$ progeny with any of the parents, D. Number of chromosome sets in plant List II: I. Back cross, II. Ploidy, III. Allele, IV. Test cross Choose the correct answer from the options given below:
- (A)
  A-II, B-I, C-III, D-IV
- (B)
  A-IV, B-III, C-II, D-I
- (C)
  A-I, B-II, C-III, D-IV
- (D)
  A-III, B-IV, C-I, D-II
14.
NEET 2024
Which one of the following can be explained on the basis of Mendel's Law of Dominance? A. Out of one pair of factors one is dominant and the other is recessive. B. Alleles do not show any expression and both the characters appear as such in $F_2$ generation. C. Factors occur in pair in normal diploid plants. D. The discrete unit controlling a particular character is called factor. E. The expression of only one of the parental characters is found in a monohybrid cross. Choose the correct answer from the options given below:
- (A)
  A, B, C, D and E
- (B)
  A, C, D and E only
- (C)
  B, C and D only
- (D)
  A, B and C only
15.
NEET 2024
Match List I with List II: List-I: A. Down's syndrome, B. $\alpha$ -Thalassemia, C. $\beta$ -Thalassemia, D. Klinefelter's List-II: I. 11th chromosome, II. 'X' chromosome, III. 21st chromosome, IV. 16th chromosome Choose the correct answer from the options given below:
- (A)
  A-II, B-III, C-IV, D-I
- (B)
  A-I, B-II, C-III, D-IV
- (C)
  A-IV, B-I, C-II, D-III
- (D)
  A-III, B-IV, C-I, D-II
16.
NEET 2024
As per ABO blood grouping system, the blood group of father is B $^+$ , mother is A $^+$ and child is O $^+$ . Their respective genotype can be A. $I^Bi / I^Ai / ii$ B. $I^BI^B / I^AI^A / ii$ C. $I^AI^B / iI^A / I^Bi$ D. $I^Ai / I^Bi / I^Ai$ E. $iI^B / iI^A / I^AI^B$ Choose the most appropriate answer from the options given below:
- (A)
  B only
- (B)
  A only
- (C)
  C & B only
- (D)
  D & E only
17.
NEET 2023
The phenomenon of pleiotropism refers to
- (A)
  more than two genes affecting a single character.
- (B)
  presence of several alleles of a single gene controlling a single crossover.
- (C)
  presence of two alleles, each of the two genes controlling a single trait.
- (D)
  a single gene affecting multiple phenotypic expression.
18.
NEET 2023
Frequency of recombination between gene pairs on same chromosome as a measure of the distance between genes to map their position on chromosome, was used for the first time by
- (A)
  Henking
- (B)
  Thomas Hunt Morgan
- (C)
  Sutton and Boveri
- (D)
  Alfred Sturtevant
19.
NEET 2023
Which of the following statements are correct about Klinefelter's Syndrome? A. This disorder was first described by Langdon Down (1866). B. Such an individual has overall masculine development. However, the feminine development is also expressed. C. The affected individual is short statured. D. Physical, psychomotor and mental development is retarded. E. Such individuals are sterile. Choose the correct answer from the options given below :
- (A)
  A and E only
- (B)
  A and B only
- (C)
  C and D only
- (D)
  B and E only
20.
NEET 2023
Broad palm with single palm crease is visible in a person suffering from-
- (A)
  Thalassemia
- (B)
  Down's syndrome
- (C)
  Turner's syndrome
- (D)
  Klinefelter's syndrome

Answer key

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