Looking for authentic SEBA Class 10 Science Chapter 9 (Heredity and Evolution) MCQ solutions for the 2026–27 academic year? Access complete multiple-choice questions on Mendel’s experiments, monohybrid and dihybrid cross ratios, sex determination, and evolutionary traits with correct options and clear explanations to score top marks in your HSLC board exams.
MCQ
Q1. Which type of reproduction shows more variation?
A) Asexual
B) Budding
C) Sexual
D) Binary fission
Answer: C) Sexual
Explanation: Sexual reproduction involves the fusion of male and female gametes from two distinct parents, resulting in genetic recombination and higher variation among offspring.
Q2. Variation is important because:
A) It causes diseases
B) It helps organisms to survive better
C) It reduces diversity
D) It makes organisms identical
Answer: B) It helps organisms to survive better
Explanation: Genetic variation provides certain individuals within a species with favorable adaptations to survive changing environmental conditions and diseases.
Q3. The passing of traits from parents to offspring is called:
A) Evolution
B) Heredity
C) Mutation
D) Variation
Answer: B) Heredity
Explanation: Heredity is the transmission of biological traits and genetic information from parents to their progeny during reproduction.
Q4. Who is known as the Father of Genetics?
A) Charles Darwin
B) J.B.S. Haldane
C) Gregor Mendel
D) Miller
Answer: C) Gregor Mendel
Explanation: Gregor Mendel earned the title “Father of Genetics” through his pioneering cross-breeding experiments with pea plants, which established the foundational laws of inheritance.
Q5. In Mendel’s monohybrid cross, the phenotypic ratio in the F2 generation was:
A) 1:2:1
B) 3:1
C) 9:3:3:1
D) 2:1
Answer: B) 3:1
Explanation: Self-pollination of the F1 hybrid tall plants produced three tall plants for every one dwarf plant in the F2 generation, resulting in a 3:1 phenotypic ratio.
HSLC Science Chapter 9 Objective Questions
Q6. Which trait was dominant in Mendel’s pea plant experiments?
A) Shortness
B) Wrinkled seeds
C) Tallness
D) White flowers
Answer: C) Tallness
Explanation: Tallness (T) masked the expressiveness of shortness (t) in the F1 generation, making tallness the dominant trait and shortness the recessive trait.
Q7. In a dihybrid cross, Mendel observed an F2 phenotypic ratio of:
A) 1:2:1
B) 3:1
C) 9:3:3:1
D) 1:1:1:1
Answer: C) 9:3:3:1 Explanation: Crossing two traits simultaneously (such as seed shape and seed color) yielded an F2 phenotypic ratio of 9 round-yellow : 3 round-green : 3 wrinkled-yellow : 1 wrinkled-green.
Q8. The basic unit responsible for inheritance of traits is a:
A) Protein
B) DNA
C) Gene
D) Chromosome
Answer: C) Gene
Explanation: A gene is a functional segment of DNA located on a chromosome that acts as the fundamental unit of inheritance controlling a specific trait.
Q9. A gene is a functional section of:
A) RNA
B) Chromosome
C) DNA
D) Ribosome
Answer: C) DNA
Explanation: Genes consist of specific sequences of DNA nucleotides that carry genetic instructions to synthesize proteins within cells.
Q10. Proteins control physical traits primarily because they:
A) Store energy
B) Control chemical reactions (as enzymes)
C) Make up chromosomes
D) Destroy DNA
Answer: B) Control chemical reactions (as enzymes)
Explanation: Genes produce enzymes (which are proteins) that catalyze specific biochemical reactions, such as hormone synthesis, which directly regulate the expression of traits.
Heredity and Evolution Class 10 SEBA MCQ Notes
Q11. Chromosomes are:
A) RNA molecules
B) Made of protein only
C) Thread-like DNA structures
D) Cell organelles
Answer: C) Thread-like DNA structures
Explanation: Chromosomes are thread-like structures located inside the nucleus, composed of tightly coiled DNA molecules and proteins that carry genetic information in the form of genes.
Q12. Humans have how many pairs of chromosomes?
A) 20
B) 22
C) 23
D) 24
Answer: C) 23
Explanation: Human somatic cells contain 46 individual chromosomes arranged in 23 pairs, consisting of 22 pairs of autosomes and 1 pair of sex chromosomes.
Q13. In humans, the sex of the child is determined by the:
A) Mother
B) Father
C) Both equally
D) Random chance
Answer: B) Father
Explanation: Mothers contribute an X chromosome through all eggs, whereas fathers produce sperm carrying either an X or a Y chromosome. The type of sperm that fertilizes the egg determines the sex of the child.
Q14. Which chromosomes are sex chromosomes in humans?
A) 1–22
B) XX and XY
C) YY and XX
D) XO and XY
Answer: B) XX and XY
Explanation: Pair 23 consists of the sex chromosomes. Females possess two X chromosomes (XX), while males possess one X and one Y chromosome (XY).
Q15. A child inheriting XY sex chromosomes will be a:
A) Boy
B) Girl
C) Twin
D) Albino
Answer: A) Boy
Explanation: The presence of the Y chromosome inherited from the father directs male sexual development, resulting in a male (XY) child.
Q16. Evolution is defined as:
A) Sudden change in traits
B) Gradual change over generations
C) Copying of DNA
D) Destruction of species
Answer: B) Gradual change over generations
Explanation: Biological evolution is the slow, continuous process through which inherited traits within populations change over successive generations, giving rise to new species.
Q17. Which of the following can lead to evolution?
A) Acquired traits
B) Inherited traits
C) Temporary changes
D) Environmental factors only
Answer: B) Inherited traits
Explanation: Only traits encoded in germ-cell DNA (inherited traits) are passed to offspring and acted upon by natural selection to drive evolutionary change.
Q18. The classic red and green beetle example illustrates:
A) Artificial selection
B) Natural selection and genetic drift
C) Mutation
D) Hybridisation
Answer: B) Natural selection and genetic drift
Explanation: The beetle population example demonstrates how natural selection (green camouflage against predators) and genetic drift (accidental stamping by an elephant) alter trait frequencies over time.
Q19. Acquired traits:
A) Are passed to offspring
B) Affect only DNA
C) Are not inherited
D) Cause speciation
Answer: C) Are not inherited
Explanation: Acquired traits develop in non-reproductive somatic tissues during an individual’s lifetime due to environmental conditions or use, so they do not alter germ-line DNA and cannot be inherited.
Q20. Speciation refers to the:
A) Mutation in genes
B) Formation of new species
C) Extinction of species
D) Mixing of genes
Answer: B) Formation of new species
Explanation: Speciation is the evolutionary process by which isolated populations diverge genetically over time until they can no longer interbreed, forming distinct new species.
Class 10 Science Chapter 9 MCQ Question Answer SEBA 2026-27
Q21. Which of the following is a cause of speciation?
A) Reproductive isolation
B) Gene flow
C) Similar environment
D) Artificial selection
Answer: A) Reproductive isolation
Explanation: Reproductive isolation prevents interbreeding between two populations, allowing distinct genetic differences to accumulate until they become separate species.
Q22. Organisms with more common features are:
A) Less related
B) Closely related
C) Unrelated
D) Not comparable
Answer: B) Closely related
Explanation: Sharing a large number of structural and genetic characteristics indicates that organisms shared a recent common evolutionary ancestor.
Q23. Evolution and classification are linked because:
A) Both depend on fossils
B) Classification reflects evolutionary relationships
C) Both study extinct species only
D) Both study body color
Answer: B) Classification reflects evolutionary relationships
Explanation: Grouping organisms based on shared similarities creates a biological classification system that directly traces their evolutionary lineage and common ancestry.
Q24. Homologous organs have:
A) Same function, different structure
B) Same structure, different function
C) Different structure and function
D) No relation
Answer: B) Same structure, different function
Explanation: Homologous organs share a common anatomical framework and evolutionary origin but have adapted to perform different functions in different species.
Q25. The wings of a bat and a bird are considered:
A) Homologous
B) Analogous
C) Vestigial
D) None of these
Answer: B) Analogous
Explanation: Bat wings and bird wings perform the same function (flying) but have different basic structural designs and origins, making them analogous organs.
Q26. Fossils help primarily in:
A) Photosynthesis
B) Studying past organisms
C) Producing energy
D) DNA replication
Answer: B) Studying past organisms
Explanation: Fossils provide direct physical remains or imprints of extinct organisms, helping scientists reconstruct ancient biological structures and evolutionary timelines.
Q27. Fossils found in deeper rock layers are generally:
A) Younger
B) Older
C) Recent
D) Unchanged
Answer: B) Older
Explanation: According to the law of superposition, sedimentary rock layers accumulate over time, meaning deeper layers were deposited earlier and contain older fossils.
Q28. The evolution of the complex eye is an example of:
A) Sudden appearance
B) Step-by-step evolution
C) Disappearance of light sensitivity
D) Random chance
Answer: B) Step-by-step evolution
Explanation: Complex organs like the eye evolved through a series of small, incremental structural improvements over time, with each intermediate stage offering a survival advantage.
Q29. Artificial selection is:
A) Done by humans
B) Done by nature
C) Caused by mutations
D) Due to fossils
Answer: A) Done by humans
Explanation: Artificial selection occurs when humans selectively breed individual plants or animals with desirable traits over successive generations.
Q30. Humans and chimpanzees:
A) Evolved from each other
B) Have no relation
C) Share a common ancestor
D) Are the same species
Answer: C) Share a common ancestor
Explanation: Neither species evolved directly from the other; instead, humans and chimpanzees diverged from a shared ancestral lineage millions of years ago.
SEBA Class 10 Science Chapter 9 MCQ Solutions
Q31. What are the two types of earlobes commonly found in humans?
A) Round and pointed
B) Free and attached
C) Long and short
D) Thick and thin
Answer: B) Free and attached
Explanation: Human earlobes are structurally categorized based on whether the earlobe hangs freely below the attachment point to the side of the head (free) or attaches directly (attached).
Q32. Which type of earlobe is dominant?
A) Attached earlobe
B) Both are equally dominant
C) Free earlobe
D) None of these
Answer: C) Free earlobe
Explanation: The allele for free earlobes is dominant over the allele for attached earlobes, meaning the presence of at least one dominant allele results in free earlobes.
Q33. Which type of earlobe is recessive?
A) Free
B) Attached
C) Both
D) None
Answer: B) Attached
Explanation: The attached earlobe trait is recessive and is only expressed phenotypically when an individual inherits two copies of the recessive allele (homozygous recessive).
Q34. If a child has free earlobes but one parent has attached earlobes, what can we conclude?
A) Child received dominant gene from the parent with free earlobes
B) Child inherited only recessive genes
C) Trait is not inherited
D) None of these
Answer: A) Child received dominant gene from the parent with free earlobes
Explanation: Since free earlobes are a dominant trait, the child requires only one dominant allele, which must come from the parent exhibiting free earlobes.
Q35. In the study of earlobes, which law of Mendel is demonstrated?
A) Law of Segregation
B) Law of Dominance
C) Law of Independent Assortment
D) Law of Evolution
Answer: B) Law of Dominance
Explanation: The inheritance pattern demonstrates Mendel’s Law of Dominance, where the dominant allele (free earlobes) masks the phenotypic expression of the recessive allele (attached earlobes).
SEBA Class 10 Science Chapter 9 Multiple Choice Questions
Q36. If both parents have attached earlobes, the child will most likely have:
A) Free earlobes
B) One free and one attached
C) Attached earlobes
D) None of these
Answer: C) Attached earlobes
Explanation: Parents with attached earlobes are homozygous recessive (ee). Since neither parent carries a dominant allele (E), they can only pass on recessive alleles, resulting in attached earlobes in offspring.
Q37. Which of the following genotype combinations represents an individual with free earlobes?
A) EE only
B) Ee only
C) Both EE and Ee
D) ee
Answer: C) Both EE and Ee
Explanation: Because free earlobes are a dominant trait, both homozygous dominant (EE) and heterozygous (Ee) genotypes express the free earlobe phenotype.
Q38. What percentage of students in a class have free earlobes if 30 out of 50 students possess them?
A) 40%
B) 50%
C) 60%
D) 70%
Answer: C) 60%
Explanation: The percentage is calculated as (30 / 50) * 100 = 60%.
Q39. The study of earlobe inheritance helps to understand:
A) Fossil formation
B) Human evolution
C) How traits are passed from parents to offspring
D) Human reproduction
Answer: C) How traits are passed from parents to offspring Explanation: Observing simple human phenotypic variations like earlobe attachment serves as a practical model for understanding mendelian inheritance patterns across generations.
Q40. What is the most suitable conclusion based on the earlobe observation activity?
A) Traits are influenced only by environment
B) Earlobe type is an inherited trait showing dominance
C) All students have identical earlobes
D) Earlobe type changes with age
Answer: B) Earlobe type is an inherited trait showing dominance Explanation: Earlobe variation is a genetically determined physical characteristic that clearly illustrates classic mendelian dominant and recessive patterns of inheritance.
🔬 Updated MCQ Guide Notice: This page features a full collection of SEBA Class 10 Science Chapter 9 (Heredity and Evolution) Multiple Choice Questions (MCQs) with accurate options and step-by-step explanations, fully updated for the 2026–27 academic session in accordance with the latest revised Assam Board (SEBA) textbook.
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