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Q1. Reproductive processes give rise to new individuals that are
Similar but subtly differentReproduction produces offspring that resemble their parents (similarity) but are not exact copies due to variations introduced during DNA copying and, in sexual reproduction, recombination. “Completely identical” occurs only in identical twins or cloning, not as a general rule. “Completely different” and “unrelated” are incorrect.
Q2. Variation is produced during
Both asexual and sexual reproductionVariations arise from inaccuracies in DNA copying (mutations) during any cell division. Asexual reproduction has low variation (only mutations). Sexual reproduction has high variation due to crossing over, independent assortment, and fusion of gametes. Growth alone (cell division without reproduction) also produces mutations but is not a reproductive context.
Q3. Sexual reproduction maximises the number of
Successful variationsSexual reproduction generates tremendous genetic diversity by combining DNA from two parents. This diversity increases the chance that some variations will be advantageous in changing environments (successful variations). It does not maximize identical traits (opposite), body designs (too vague), or chromosome number (which remains constant per species).
Q4. Paddy plants show very little variation because they
Reproduce asexuallyPaddy (rice) is typically self-pollinating, which is a form of sexual reproduction but with the same plant as both parents, leading to very low genetic variation compared to cross-pollinating plants. However, in many contexts, cultivated rice shows low variation due to vegetative propagation (asexual) or selfing. The key point: low variation correlates with limited genetic exchange.
Q5. Large visible variations are commonly seen in
Animals and human beingsAnimals (including humans) show extensive visible variations (height, eye color, skin color, body shape) because they reproduce sexually, have large genomes, and are diploid. Bacteria show variation but not “large visible” ones. Paddy and algae appear relatively uniform to the naked eye.
Q6. The study of how variations are created and inherited is called
GeneticsGenetics is the branch of biology that studies genes, genetic variation, and heredity in living organisms. Ecology studies interactions between organisms and environment. Evolution studies change over long time scales. Taxonomy classifies organisms.
Q7. Long-term accumulation of variations is studied under
EvolutionEvolution is the change in heritable characteristics of populations over successive generations, driven by accumulation of variations and natural selection. Growth, reproduction, and nutrition are short-term or individual-level processes, not long-term accumulation across generations.
Q8. Inheritance provides the next generation with
Basic body design and subtle changesInheritance transmits the species-specific body plan (basic design) from parents, along with subtle variations (differences) that make each individual unique. It does not provide “only variations” or “completely new designs” (which would break species continuity).
Q9. The second generation inherits
Inherited and newly created variationsThe second generation (F₂) receives variations that existed in the first generation (inherited) plus any new mutations that occurred during gamete formation in the F₁ generation. Thus, it is a mix of old and new variations.
Q10. In asexual reproduction, repeated division of one bacterium produces individuals that are
Completely identicalIn binary fission (asexual reproduction in bacteria), the DNA is copied and the cell divides. Barring rare mutations, all offspring are genetically identical clones of the parent. “Very similar” is also true, but “completely identical” is the more precise description for no-mutation conditions.
Q11. Minor differences in asexual reproduction arise due to
Inaccuracies in DNA copyingEven in asexual reproduction, DNA replication is not 100% perfect. Occasional errors (mutations) introduce minor differences. Fertilisation does not occur in asexual reproduction. Environmental changes affect phenotype but not genotype directly. “Mutation only” is essentially the same as C, but C is more specific to the copying process.
Q12. Sexual reproduction produces greater diversity because
Two individuals are involvedTwo parents contribute genetic material, which recombines during meiosis and fertilization. This creates novel combinations of alleles. DNA copying is not perfect (errors still occur). Only one parent (as in asexual) reduces diversity. Cell division speed is unrelated to diversity.
Q13. In sexual reproduction, each generation shows
New combinations of traitsSexual reproduction shuffles existing alleles into new combinations through crossing over and independent assortment. Offspring are not exact copies of either parent; they show unique trait combinations. Inheritance does occur (not absent), and variation is not lost but recombined.
Q14. Variations do not have equal chances of survival because
Environment selects useful variationsNatural selection favors variations that enhance survival and reproduction in a given environment. Harmful variations reduce survival chances. Environments are not all the same; not all traits are harmful; DNA does not stop copying. This is the core of Darwinian selection.
Q15. Bacteria resistant to heat survive better during
Heat wavesHeat-resistant bacteria have a survival advantage when environmental temperature rises (heat waves). Floods, cold waves, and droughts select for different traits (e.g., cold resistance, desiccation resistance). This illustrates environment-specific selection.
Q16. Selection of variants by environment forms the basis of
EvolutionNatural selection (environment selecting advantageous variants) is the primary mechanism of evolution. Over generations, favorable traits become more common in the population. Reproduction, heredity, and growth are necessary for evolution but are not the basis of the selection process itself.
Q17. If trait B exists in 60% of a population, it is likely to have
Appeared earlierA trait present in a high percentage (60%) of a population likely arose earlier in evolutionary time, allowing more generations for it to spread (especially if advantageous or neutral). A recent trait would be at low frequency. The trait may or may not have advantage, but high frequency suggests earlier origin.
Q18. Creation of variations promotes survival because
Some individuals become better adaptedVariation ensures that at least some individuals in a population possess traits suited to changing environmental conditions. These better-adapted individuals survive and reproduce. Identical individuals would all be vulnerable to the same threats. Environments change, and DNA continues to change (mutate).
Q19. Heredity mainly deals with
Transmission of traitsHeredity is the passing of genetic traits from parents to offspring. Growth, nutrition, and respiration are physiological processes, not the focus of heredity.
Q20. The most obvious outcome of reproduction is
Individuals of similar designReproduction produces new individuals that resemble their parents (same species, same basic body plan). Variation is present but less obvious than similarity. Death is not an outcome of reproduction; it is an outcome of aging. Mutation is a mechanism, not the primary observable outcome.
Q21. Rules of heredity explain how traits are
Reliably inheritedMendel’s laws (segregation, independent assortment) explain the predictable patterns by which traits are passed from parents to offspring. Traits are not destroyed, randomly formed, or removed (though they can be masked or recombined).
Q22. Children resemble parents because
They inherit traitsResemblance is due to genetic inheritance (DNA passed from parents to offspring). Diet, environment, and growth patterns can influence phenotype but are not the primary cause of familial resemblance. Identical twins raised apart still resemble each other.
Q23. Human populations show large variation because
Reproduction is sexualHumans reproduce sexually, with two parents contributing recombined DNA. This generates immense genetic diversity. DNA is reasonably stable (mutations are rare per generation). Environment is not fixed and contributes to phenotypic variation, but genetic variation is primarily due to sexual reproduction.
Q24. Earlobes in humans occur mainly in
Two variantsHuman earlobes are typically classified into two main variants: free (detached) and attached. While continuous variation exists, the classical Mendelian trait is taught as two distinct forms. Three or many shapes overcomplicate the basic genetic concept.
Q25. Free and attached earlobes are examples of
Inherited traitsEarlobe type is determined by genes and passed from parents to offspring. It is not acquired during life, not a disease, and not solely due to mutation (though mutations can alter it). It is a classic example of an inherited Mendelian trait in humans.
Q26. The lowest part of the ear is called the
EarlobeThe earlobe (lobule) is the soft, fleshy lower part of the external ear. The pinna is the entire visible outer ear. Cochlea is part of the inner ear (hearing). The ear canal is the tube leading to the eardrum.
Q27. In inheritance, both parents contribute
Equal genetic materialIn sexual reproduction, each parent contributes one haploid set of chromosomes (23 in humans) via gametes (sperm and egg). Thus, genetic contribution is equal. Traits are encoded in genes on chromosomes, so “only chromosomes” is too narrow (they contribute genes, not just chromosomes as structures).
Q28. Each trait in a child has
Two versionsFor each gene (trait), a child inherits one allele from the mother and one from the father (diploid). These two versions may be identical (homozygous) or different (heterozygous). Many versions exist in the population but each individual has at most two.
Q29. Traits in a child are influenced by
Both maternal and paternal DNAThe child’s nuclear DNA is 50% from mother and 50% from father. Both contribute equally to inherited traits. Environment also influences traits (phenotype), but the question specifies genetic influence, so both parents contribute DNA.
Q30. The scientist who proposed rules of inheritance was
MendelGregor Mendel, through his pea plant experiments (1856-1863), formulated the fundamental laws of inheritance (segregation, independent assortment). Darwin proposed evolution by natural selection, Lamarck proposed inheritance of acquired characteristics, and Watson (with Crick) discovered DNA structure.
Q31. Mendel’s experiments were conducted more than
150 years agoMendel’s experiments were published in 1865-1866, which is over 150 years ago (as of 2026, it is ~160 years). 50, 75, and 100 years are incorrect as they would place his work in the mid-20th century, long after his rediscovery in 1900.
Q32. The rules of inheritance help explain
Trait expressionInheritance rules explain how traits (phenotypes) are passed from parents to offspring and how they appear (expressed) in individuals. Growth rate, body size, and nutrition are influenced by both genetics and environment, but the core of inheritance rules is trait transmission and expression.
Q33. Two individuals of the same species differ mainly due to
Genetic variationsThe primary cause of differences between individuals of the same species is genetic variation (different alleles). Habitat, habits, and food intake cause phenotypic differences (non-heritable) but are not the main reason for inherent differences. Identical twins raised apart still show genetic similarity despite different environments.
Q34. Accumulation of variations occurs over
Many generationsVariation accumulation is a gradual process across many generations. Each generation adds new mutations and recombinations. One or two generations are insufficient for significant accumulation. One lifetime refers to an individual, not a population.
Q35. In asexual reproduction, diversity generation is
Very lowAsexual reproduction produces clones (genetically identical except for rare mutations). Diversity generation is very low compared to sexual reproduction. It is not completely absent because mutations do occur, but frequency is extremely low.
Q36. Sexual reproduction increases diversity by
Combining variationsSexual reproduction brings together genetic material from two parents, combining their different variations (alleles) into new unique combinations. DNA is not reduced (it is halved in gametes but restored in zygote). Mutations are not eliminated; inheritance is not prevented.
Q37. Variations that are harmful are usually
EliminatedHarmful variations reduce an organism’s survival or reproductive success. Natural selection acts against them, and they tend to be eliminated from the population over generations. They are not preserved, selected for, or always inherited (though they can be inherited but will be selected against).
Q38. Useful variations are
Selected by environmentUseful (advantageous) variations increase survival and reproduction. The environment “selects” them, causing these traits to become more common in the population over generations (natural selection). They are not destroyed, ignored, or non-inheritable.
Q39. Variation is essential for
Species survivalVariation allows a species to adapt to changing environments, resist diseases, and avoid extinction. Without variation, a single environmental change could wipe out the entire uniform population. Individual survival is important but variation benefits the species long-term. Growth and digestion are unrelated.
Q40. Greater diversity gives organisms
More chances of survivalGreater genetic diversity increases the likelihood that some individuals will possess traits suited to environmental changes (disease, climate, predators). This enhances population survival. Diversity is the opposite of uniformity; it generally increases stability, not reduces it.
Q41. Differences inherited from parents are called
Inherited traitsInherited traits are characteristics passed from parents to offspring via genes. Acquired traits are developed during life (e.g., muscle from exercise). Learned traits are acquired through experience. Inherited traits are permanent (genetic), not temporary.
Q42. The study of inheritance patterns is central to
GeneticsGenetics is the branch of biology that specifically studies inheritance, genes, and variation. Ecology studies interactions with environment, geography studies Earth’s features, and anatomy studies body structure.
Q43. In sexual reproduction, each individual is
Genetically uniqueExcept for identical twins (rare), every sexually produced individual has a unique combination of alleles due to crossing over, independent assortment, and random fertilization. No two siblings (other than identical twins) are genetically identical. Sterility is not a general outcome.
Q44. Minor DNA copying errors are a source of
VariationDNA replication errors (mutations) are the ultimate source of all genetic variation. Most are neutral, some are harmful (cause disease), and rarely beneficial. But their primary significance in evolutionary biology is as the origin of variation. They do not cause “death only” or “no effect” as a rule.
Q45. Accumulated variations over time lead to
EvolutionAccumulation of heritable variations in a population over generations, combined with natural selection, leads to evolutionary change (adaptation, speciation). Stability is the opposite; extinction is one possible outcome but not the only one; change does occur.
Q46. Heredity ensures continuity of
TraitsHeredity is the transmission of genetic traits from parents to offspring, ensuring that characteristics of a species persist across generations. Environment, nutrition, and energy are not directly ensured by heredity.
Q47. A trait seen in many individuals is likely to be
Older in originA trait that is common (high frequency) in a population has likely been present for many generations, allowing time for it to spread (if advantageous or neutral). Recent traits start at low frequency. Harmful traits do not become common. Non-heritable traits cannot become common across generations.
Q48. Sexual reproduction is more effective in generating variation because
Two DNA sets combineThe fusion of two different genomes (from two parents) creates new allele combinations that never existed before. DNA inaccuracies (mutations) occur in both sexual and asexual reproduction. Cell division speed and growth rate are unrelated to variation generation.
Q49. The main difference between sexual and asexual reproduction is
Number of parents involvedSexual reproduction involves two parents (contribution of gametes), while asexual reproduction involves a single parent. This is the fundamental distinction. Growth rate, body size, and nutrition are not defining differences.
Q50. Genetics helps us understand
Similarities and differences among individualsGenetics explains why individuals resemble each other (inheritance) and why they differ (variation). It also helps understand diseases and growth, but the broadest and most accurate answer is that it explains both similarities and differences. Nutrition patterns are primarily studied in physiology.