Pre AP Biology -EVO 1.1 Theory of Evolution- MCQ Exam Style Questions -New Syllabus 2025-2026
Pre AP Biology -EVO 1.1 Theory of Evolution- MCQ Exam Style Questions – New Syllabus 2025-2026
Pre AP Biology -EVO 1.1 Theory of Evolution- MCQ Exam Style Questions – Pre AP Biology – per latest Pre AP Biology Syllabus.
▶️ Answer/Explanation
The correct answer is b. slugs.
A radula is a specialized anatomical structure found in mollusks.
It functions as a chitinous, toothed ribbon used for scraping or cutting food.
Slugs and snails belong to the class Gastropoda, which characteristically possess this organ.
Lobsters (arthropods) use mandibles rather than a radula for feeding.
Worms (like annelids) and corals (cnidarians) lack this specific molluscan structure.
Therefore, among the choices provided, only the slug possesses a radula.
▶️ Answer/Explanation
The correct answer is d. Bivalvia.
Clams, scallops, and mussels all belong to the phylum Mollusca.
They are specifically categorized under the class Bivalvia because they possess two hinged shells (valves).
Cephalopoda includes organisms like octopuses and squids with prominent heads and tentacles.
Scaphopoda refers to “tusk shells,” which are elongated and tubular.
Gastropoda includes snails and slugs, which typically have a single spiral shell or no shell at all.
Therefore, a dish with clams, scallops, and mussels consists entirely of Bivalves.
▶️ Answer/Explanation
The phylum Chordata is defined by four primary diagnostic characteristics.
All chordates possess a notochord, which provides skeletal support.
They feature a dorsal hollow nerve cord that develops into the central nervous system.
Pharyngeal slits (or gill slits) are present at some stage of development.
A post-anal tail is a muscular extension extending past the anus.
These four traits must appear during the life cycle for an animal to be a chordate.
Therefore, the correct option is d.
▶️ Answer/Explanation
The correct answer is b. secondary radial.
Echinoderms are evolutionarily derived from bilaterally symmetrical ancestors.
Their larval stages exhibit bilateral symmetry, which is considered their primary state.
During metamorphosis, they develop penta-radial symmetry as adults.
Because the radial symmetry is acquired later in the life cycle, it is termed secondary radial symmetry.
This adaptation is thought to be an evolutionary shift related to a sedentary or slow-moving lifestyle.
▶️ Answer/Explanation
The correct option is c. Arthropoda.
Phylum Arthropoda is the largest phylum in the animal kingdom.
It includes insects, spiders, and crustaceans, accounting for over $80\%$ of all known animal species.
Scientists have identified over $1,000,000$ distinct species within this group.
Their success is due to features like a chitinous exoskeleton and jointed appendages.
In comparison, Phylum Chordata and others have significantly fewer described species.
This vast diversity makes Arthropoda the most species-rich taxon on Earth.
▶️ Answer/Explanation
The correct answer is c.
In protostomes, the early embryonic cells divide at an angle, known as spiral cleavage.
Deuterostomes, by contrast, exhibit radial cleavage where cells align directly atop one another.
The term “protostome” literally means “first mouth,” as the blastopore becomes the mouth, not the anus.
Coelom formation in protostomes occurs via schizocoely (splitting of mesoderm), unlike the outpocketing seen in deuterostomes.
Both groups are classified as animals within the clade Bilateria.
Therefore, spiral cleavage is a definitive developmental hallmark of the protostome lineage.
▶️ Answer/Explanation
Gametangia (protective structures for gametes) appeared first in early non-vascular land plants (bryophytes).
Vascular tissue (xylem and phloem) evolved next, allowing plants to grow taller (seedless vascular plants).
Seeds evolved later to protect the embryo and allow dispersal without water (gymnosperms).
Flowers are the most recent adaptation, evolving to enhance pollination efficiency (angiosperms).
The correct chronological sequence is therefore: gametangia $\rightarrow$ vascular tissue $\rightarrow$ seeds $\rightarrow$ flowers.
Thus, the correct option is d.
▶️ Answer/Explanation
Horsetails belong to the group Monilophyta.
This group also includes ferns and whisk ferns.
They are all seedless vascular plants.
Molecular data shows they share a more recent common ancestor with each other than with lycophytes.
Mosses, liverworts, and hornworts are non-vascular bryophytes.
Gymnosperms and gnetophytes are seed-bearing plants.
Therefore, the correct answer is a.
▶️ Answer/Explanation
The correct answer is b.
Horsetails belong to the phylum Pterophyta (or Monilophyta), which includes ferns and whisk ferns.
Cycads belong to Cycadophyta, while Hepatophyta refers to liverworts.
Gnetophytes belong to Gnetophyta, while Bryophyta refers to mosses.
Angiosperms belong to Anthophyta, while Coniferophyta refers to conifers like pines.
Therefore, only option b provides a matching pair of a plant group and its biological phylum.
▶️ Answer/Explanation
The correct option is c. seeds and pollen.
Pollen allows for the transfer of male gametes via wind or animals instead of swimming through water.
Seeds protect the embryo and provide nutrients, allowing for survival in dry environments.
Earlier plants like ferns and mosses require a film of moisture for sperm to reach the egg.
Lignified stems and roots assist with structural support and water transport, not reproduction.
Flowers and fruits are later innovations that primarily aid in pollination efficiency and seed dispersal.
Therefore, seeds and pollen were the primary “independence” factors from external water sources.
▶️ Answer/Explanation
The correct option is d.
Both mosses (bryophytes) and angiosperms exhibit alternation of generations.
The sporophyte ($2n$) is the diploid phase that undergoes meiosis.
Through the process of meiosis, the sporophyte produces haploid spores ($n$).
In mosses, the gametophyte is dominant, while in angiosperms, the sporophyte is dominant.
However, the function of the sporophyte to produce spores remains a universal trait in both.
Spores actually develop into gametophytes, making option c biologically incorrect.
▶️ Answer/Explanation
The correct option is c.
Deuteromycota is often referred to as a “taxonomic holding pen” or Fungi Imperfecti.
Fungi are typically classified into phyla based on the structures they form during sexual reproduction.
In Deuteromycetes, the sexual (teleomorph) stage has not been observed or is non-existent.
These fungi reproduce primarily through asexual means, such as the production of conidia.
Once a sexual stage is discovered for a species, it is moved to a formal phylum like Ascomycota or Basidiomycota.
Therefore, the lack of a known sexual cycle is the defining reason for this classification.
▶️ Answer/Explanation
Correct Option: a
Diplomonads are unicellular protists that belong to the supergroup Excavata.
They are uniquely identified by having two equal-sized, functional nuclei.
They possess multiple flagella for locomotion but lack typical mitochondria.
Instead of normal mitochondria, they have reduced organelles called mitosomes.
A well-known example is Giardia lamblia, an intestinal parasite.
Options b, c, and d describe Ciliates, Apicomplexans, and Kinetoplastids respectively.
▶️ Answer/Explanation
The correct answer is d.
According to the endosymbiotic theory, chloroplasts originated from a primary endosymbiotic event.
This involved a large, non-photosynthetic eukaryote engulfing a free-living photosynthetic prokaryote.
The prokaryote was likely an ancestral cyanobacterium capable of performing photosynthesis.
The inner membrane of the chloroplast corresponds to the original prokaryotic plasma membrane.
The outer membrane is derived from the engulfing vacuole (phagosomal membrane) of the eukaryotic host.
This $1$ host plus $1$ endosymbiont relationship explains the double-membrane structure found in primary algae.
Other options like c refer to secondary endosymbiosis, which results in more than $2$ membranes.
▶️ Answer/Explanation
The correct option is d.
Cellular slime moulds are heterotrophic protists, not autotrophs.
They move using pseudopodia (amoeboid movement) rather than cilia.
They can reproduce both sexually (forming macrocysts) and asexually.
When food is scarce, individual cells aggregate to form a pseudoplasmodium.
This aggregate develops into a fruiting body (sorocarp) to release spores.
The spores are resistant structures that allow for dispersal and survival in harsh conditions.
▶️ Answer/Explanation
The correct answer is b. foraminiferans.
Foraminiferans are marine protists that live in porous shells called tests.
These shells are usually made of calcium carbonate ($CaCO_{3}$).
Over millions of years, these shells settle on the ocean floor and form sedimentary rock.
The presence of these fossilized shells is a key geological marker for oil-bearing strata.
Petroleum geologists use these microfossils to date rock layers and locate oil deposits.
While diatoms also have shells, they are made of silica ($SiO_{2}$) and are less specific indicators for oil.
▶️ Answer/Explanation
The correct answer is c. green algae.
Land plants and green algae (specifically charophytes) share a most recent common ancestor.
Both groups possess chlorophyll $a$ and chlorophyll $b$ for photosynthesis.
They both utilize cellulose in their cell walls to provide structural support.
Energy is stored as starch inside chloroplasts in both land plants and green algae.
Molecular DNA sequencing confirms a close phylogenetic relationship between them.
▶️ Answer/Explanation
The correct answer is d. apicomplexans.
Plasmodium is a genus of unicellular eukaryotes that are obligate parasites.
They belong to the group Apicomplexa, characterized by a complex of organelles at their apical end.
These organisms typically have complex life cycles involving both asexual and sexual phases.
They produce sporozoites, which are the infective stage transmitted via the Anopheles mosquito.
Unlike euglenoids or dinoflagellates, they lack structures for locomotion like flagella in their mature adult stages.
Apicomplexans are notorious for causing diseases such as malaria in humans.
▶️ Answer/Explanation
The correct option is b. brown algae.
Brown algae (Phaeophyceae) are multicellular marine organisms.
They possess gas-filled bladders (pneumatocysts) for buoyancy.
Their cell walls contain alginic acid, a complex polysaccharide.
Diatoms and golden algae typically have walls made of silica or different polymers.
Oomycetes are fungus-like protists with cellulose-based cell walls.
Alginic acid is specifically extracted commercially from brown seaweed.
▶️ Answer/Explanation
The correct answer is d. diatoms.
Diatoms are unicellular algae characterized by unique glass-like walls made of silicon dioxide ($\text{SiO}_2$).
These sturdy shells, known as frustules, do not decompose easily after the organism dies.
Massive accumulations of these ancient shells sink to the ocean floor, forming thick layers of diatomaceous earth.
Among the options, diatoms have the highest preservation rate due to this mineralized structure.
Other groups like oomycetes or soft-bodied algae lack the hard parts necessary to dominate the fossil record.
This makes diatoms the primary contributors to protist-based sedimentary fossil deposits.
▶️ Answer/Explanation
The correct answer is a.
Archaea are characterized by cell walls that lack peptidoglycan, unlike Bacteria.
Their membrane lipids contain branched hydrocarbons, which distinguish them from the unbranched lipids of Bacteria.
Both Bacteria and Archaea typically possess circular DNA and lack a nuclear envelope.
Therefore, presence of peptidoglycan (option b) would indicate a bacterium.
The presence of a nuclear envelope (option c) or linear DNA (option d) would typically indicate a eukaryote.
▶️ Answer/Explanation
The correct answer is c. Many are extremophiles.
Archaea are known for living in harsh environments like hot springs or salt lakes.
Unlike Bacteria, Archaea lack peptidoglycan in their cell walls.
There are currently no known pathogenic species of Archaea.
They share several molecular traits with Eukaryotes, such as similar RNA polymerases.
Their membranes often contain unique ether-linked lipids to survive extreme conditions.
This distinct lineage represents one of the three primary domains of life.
▶️ Answer/Explanation
The correct answer is c. They had supportive cuticle.
Ediacaran biota were primarily soft-bodied organisms lacking biomineralized skeletons.
Hard parts like bones or exoskeletons (options b and d) would lead to mineral fossilization.
The presence of a tough, organic supportive cuticle allowed for impressions to be preserved.
These fossils often appear as molds or casts in sandstone or shale.
Cell walls (option a) are characteristic of plants and fungi, not these early animal-like forms.
Therefore, a non-mineralized cuticle is the best explanation for their unique fossilization style.
▶️ Answer/Explanation
The correct answer is d. A birdlike body may be a result of convergent evolution.
Convergent evolution occurs when unrelated species evolve similar physical traits independently.
This happens because the organisms adapt to similar environments or ecological niches.
A “birdlike” external appearance does not guarantee a common ancestry with birds.
Examining skeletal details helps distinguish between analogous structures and homologous ones.
This prevents misclassifying an organism based purely on superficial functional similarities.
Therefore, skeletal analysis is essential to confirm the phylogenetic lineage of the fossil.
▶️ Answer/Explanation
Correct Option: b
Homoplasy refers to traits shared by species that are not present in their common ancestor.
The wing of a bird and the wing of a fly evolved independently to serve the same function (flight).
Birds are vertebrates with endoskeletons, while flies are insects with chitinous exoskeletons.
Since they do not share a winged common ancestor, this is an example of convergent evolution.
In contrast, the skeletons in option a are homologous because they share a common tetrapod ancestor.
The eyes in option c are also homologous as they share the basic vertebrate eye plan.
Option d involves homologous limb bones but homoplasious flight surfaces.
▶️ Answer/Explanation
The correct option is a.
Systematics relies on the premise that physical and behavioral traits are heritable.
Morphological features are outward expressions of an organism’s genotype.
Therefore, similarities in these traits suggest a shared genetic ancestry.
If traits were only environmental (option d), they would not indicate evolutionary relationships.
Reconstructing a phylogeny assumes that phenotypic Divergence ($\Delta P$) correlates with Genetic Divergence ($\Delta G$).
This allows scientists to group animals based on homologous characters derived from a common ancestor.
▶️ Answer/Explanation
In binomial nomenclature, the first word ($Ursus$) represents the genus.
The second word ($maritimus$ or $arctos$) represents the specific epithet or species.
Since both bears share the same first name, $Ursus$, they belong to the same genus.
Because they have different second names, they are different species.
In biological hierarchy, organisms in the same genus must also belong to the same family.
Therefore, they share the same genus and family, making (b) the correct conclusion.
▶️ Answer/Explanation
Evolution via natural selection is a reactive process, not a predictive one.
Adaptations occur because specific traits provided a survival advantage in past environments.
Natural selection preserves alleles that were successful in previous generations.
Because mutations are random, the process cannot “foresee” future environmental shifts.
Organisms often carry “evolutionary baggage” suited for historical conditions.
Therefore, current traits reflect the selective pressures of the ancestral habitat.
If an environment changes rapidly, a species may possess traits that are no longer optimal.
▶️ Answer/Explanation
The correct option is d.
Charles Darwin noted that extinct fossils often resemble living species in the same region.
The glyptodont and the armadillo share a unique bony shell structure.
Visible anatomical similarities are primary evidence for common ancestry in paleontology.
Living at different times (option a) describes their existence but doesn’t prove a biological link.
Body size (option c) is incorrect, as glyptodonts were much larger, roughly the size of a $1,000$ kg car.
Therefore, morphological resemblance is the strongest factor for this hypothesis.
▶️ Answer/Explanation
The correct option is d. descent with modification.
Bioinformatics relies on comparing $DNA$ or protein sequences to find similarities.
High sequence similarity suggests that organisms share a common ancestor.
The differences in these sequences are the result of mutations accumulating over time.
This process of evolving from a common ancestor with changes is known as descent with modification.
Without this evolutionary framework, sequence comparisons would have no biological context.
Other options like $Lamarckism$ or $perfection$ are scientifically outdated or irrelevant to sequence alignment.
▶️ Answer/Explanation
The correct answer is c. Carolus Linnaeus.
Natural theology is the study of nature to discover the Creator’s plan.
Linnaeus sought to classify species to reveal the divine order of life.
He famously stated, “God created, Linnaeus organized.”
Aristotle influenced biology but predates the formal concept of natural theology.
Lamarck and Darwin proposed mechanisms for evolution, which often challenged these views.
Linnaeus remains the most prominent early figure linking taxonomy with natural theology.
▶️ Answer/Explanation
The correct option is c.
Darwin used the phrase “descent with modification” to describe the process of evolution.
It implies that all organisms are related through descent from a common ancestor.
Over vast periods of time, natural selection acts on these lineages.
As populations migrate to different habitats, they accumulate modifications (adaptations).
These changes allow them to survive and reproduce in their specific environments.
This process explains both the unity of life and the diversity of species seen today.
▶️ Answer/Explanation
The correct answer is b. homologous structures.
Homologous structures are organs or skeletal elements that, by virtue of their similarity, suggest a common ancestry.
Bats, pigs, and dolphins are all mammals that share a common tetrapod ancestor.
While these appendages perform different functions (flying, walking, swimming), they share a similar underlying bone structure.
This anatomical correspondence is a result of divergent evolution from a single ancestral template.
In contrast, vestigial structures are remnants of organs that have lost their original function over time.
Acquired characteristics and artificial selection do not describe these specific anatomical relationships.
▶️ Answer/Explanation
Aristotle proposed the Scala Naturae, or the “Great Chain of Being.”
This concept visualized life as a linear ladder of increasing complexity.
He placed inanimate matter at the bottom and humans at the top.
In this hierarchy, humans were viewed as the most complex beings, sitting just below perfection.
This model suggested that species were fixed and did not evolve over time.
Therefore, the correct option is c.
▶️ Answer/Explanation
The correct answer is a.
Protein domains are structural units that can fold and function independently.
Partial $DNA$ sequence similarity suggests that only specific regions are conserved.
These conserved regions often encode shared functional or structural domains.
Full gene duplication (option b) would typically result in similarity across the entire sequence.
Proteins with shared domains may have different overall functions (option c).
A pseudogene (option d) is a non-functional version of a gene and isn’t implied by partial similarity.
▶️ Answer/Explanation
The correct option is d.
The experiment simulated Earth’s primitive reducing atmosphere ($CH_4, NH_3, H_2, H_2O$).
Electrical sparks were used to simulate lightning as an energy source.
Within a week, several organic compounds, including amino acids, were produced.
This proved that organic “building blocks” could arise from inorganic precursors.
It supported the Oparin-Haldane hypothesis of abiotic synthesis.
Crucially, the experiment succeeded specifically because $O_2$ was absent.
▶️ Answer/Explanation
The correct answer is (b).
The discovery of ribozymes ($\text{RNA}$ catalysts) supports the RNA World hypothesis.
It proves $\text{RNA}$ can store genetic information while simultaneously performing enzymatic functions.
This explains how early life could function without the complex $\text{DNA}$ → Protein feedback loop.
$\text{RNA}$ likely catalyzed its own replication before the emergence of stable $\text{DNA}$ and protein enzymes.
This solved the paradox of which molecule—genetic or functional—preceded the other in evolution.
▶️ Answer/Explanation
The correct answer is c.
Asgard archaea possess Eukaryotic Signature Proteins ($ESPs$).
These genes were previously thought to be unique to the domain $Eukaryota$.
They include genes for cytoskeletal components like actin and tubulin-like proteins.
They also contain genes for membrane remodeling and intracellular trafficking.
This genomic evidence places Asgard archaea as the closest prokaryotic relatives to eukaryotes.
Options a and b are incorrect as Asgard cells lack true membrane-bound nuclei or mitochondria.
▶️ Answer/Explanation
The correct answer is c.
Anoxygenic photosynthesis evolved first, using molecules like $\text{H}_2\text{S}$ instead of $\text{H}_2\text{O}$.
Oxygenic photosynthesis developed later, producing free oxygen as a byproduct.
This led to the accumulation of $\text{O}_2$ in the atmosphere (the Great Oxidation Event).
Aerobic respiration then evolved to utilize this new atmospheric oxygen for efficient energy production.
This sequence follows the logical progression of metabolic complexity and environmental change.
▶️ Answer/Explanation
The correct option is b.
The endosymbiotic theory suggests that organelles like mitochondria and chloroplasts were once free-living prokaryotes.
Evidence includes the fact that these organelles contain their own circular DNA (genomes), similar to bacteria.
They also possess their own $70S$ ribosomes and replicate independently via binary fission.
Option a and c describe general cellular features not unique to endosymbionts.
Option d refers to the autogenous hypothesis for the nucleus, not endosymbiosis.
▶️ Answer/Explanation
The correct option is d. endoplasmic reticulum.
According to the autogenous hypothesis, the endomembrane system evolved from the inward folding of the prokaryotic plasma membrane.
This process created internal compartments like the nuclear envelope and the endoplasmic reticulum (\(\text{ER}\)).
Infolding increased the surface area-to-volume ratio, allowing for more efficient metabolic processes.
Unlike the \(\text{ER}\), mitochondria (option c) are thought to have evolved through endosymbiosis, not simple infolding.
Ribosomes (option a) are non-membrane-bound complexes of \(\text{RNA}\) and protein, not formed from membrane folds.
Microtubules (option b) are protein filaments that make up the cytoskeleton, not derived from the plasma membrane.
▶️ Answer/Explanation
The correct answer is B.
While all living things share a universal genetic code (DNA/RNA) and basic metabolism, they do not all share complex organelles.
Prokaryotes (bacteria and archaea) lack membrane-bound organelles like mitochondria.
Additionally, prokaryotes typically possess circular chromosomes, whereas linear chromosomes are characteristic of eukaryotes.
Options A, C, and D describe molecular homologies found across all domains of life (Archaea, Bacteria, and Eukarya).
Therefore, the presence of mitochondria is not a universal piece of evidence for all living things sharing a common ancestor.
Instead, mitochondria provide evidence for the shared ancestry of eukaryotes specifically via endosymbiosis.
▶️ Answer/Explanation
The correct option is C.
The human coccyx is a vestigial structure because it is a remnant of a tail found in ancestral species.
In humans, it no longer serves the primary purpose of balance or grasping as it does in other primates.
A vestigial structure is defined as a part of the body that has lost all or most of its original function through evolution.
While the coccyx still serves as an attachment point for muscles, it is a reduced version of a functional tail.
Analogous structures (Option A) have similar functions but different evolutionary origins.
Homologous structures (Option B) share an origin but may have different current functions.
▶️ Answer/Explanation
Vestigial structures are anatomical remnants that were fully functional in an ancestor.
Over time, these structures have lost most or all of their original ancestral function.
In flightless birds, wings are reduced in size because they no longer serve the purpose of flight.
These structures provide evidence for evolution by showing how species change over generations.
While they may gain new functions (like penguin wings becoming flippers), their original use is gone.
This distinguishes them from homologous structures (shared ancestry) or analogous structures (shared function).
▶️ Answer/Explanation
The correct answer is B. Analogous structures.
Analogous structures perform the same function (such as flying) but have different evolutionary origins.
These structures arise through convergent evolution, where different species adapt to similar environments.
Unlike homologous structures, they do not reflect a shared recent common ancestor.
Examples include the wings of a butterfly (chitin) versus the wings of a bird (bone and feathers).
Homologous structures (Option A) share a common origin but may have different functions.
Vestigial structures (Option C) are remnants of organs that served a purpose in ancestors but are no longer functional.
▶️ Answer/Explanation
The correct answer is A.
Lamarck proposed the theory of “Inheritance of Acquired Characteristics.”
This suggested that traits developed during an organism’s lifetime could be passed to offspring.
Modern genetics shows that only changes in the DNA of germ cells are heritable.
Phenotypic changes from use or disuse do not alter the underlying genetic code.
In contrast, options B, C, and D remain fundamental pillars of evolutionary biology today.
Therefore, the idea that acquired traits are inherited was proven incorrect.
▶️ Answer/Explanation
The correct answer is B.
A scientific theory is much broader than a single hypothesis or a specific experimental conclusion.
It represents a thoroughly tested explanation for a set of natural phenomena.
Theories serve to unify multiple independent observations and data points into a cohesive framework.
Unlike a hypothesis, which is a preliminary guess, a theory is supported by extensive evidence.
It allows scientists to make accurate predictions about future observations or experiments.
While a theory is robust, it remains open to refinement if new contradictory evidence arises.
▶️ Answer/Explanation
The correct option is D.
Peer review acts as a quality control filter for scientific research.
Experts in the same field evaluate the methodology and data for accuracy.
This process ensures that conclusions are logically supported by evidence.
It prevents the publication of flawed or fraudulent scientific work.
Ultimately, it maintains high professional standards within the community.
Options A, B, and C describe funding, popularity, or quantity, which are not the goals of peer review.
▶️ Answer/Explanation
The correct option is B.
An observation is information gathered directly through the five senses.
An inference is a conclusion drawn based on those observations and prior knowledge.
Option A is incorrect because observations are data, while inferences are explanations.
Option C describes quantitative data, not necessarily an inference.
Option D is incorrect as inferences can still be subject to personal bias.
Therefore, an inference is best defined as a logical interpretation of what has been observed.
▶️ Answer/Explanation
Correct Option: D
Comparing DNA sequences provides the most objective and precise data for classification.
Physical traits (A) can be misleading due to convergent evolution or environmental factors.
Cellular structures (B) and feeding habits (C) often overlap significantly across different genera.
Modern taxonomy relies on molecular phylogenetics to identify unique genetic markers.
A distinct genetic signature confirms reproductive isolation and evolutionary divergence.
Therefore, DNA analysis is the best and most definitive method for identifying a new species.
▶️ Answer/Explanation
Nucleotide sequences (DNA) provide the most direct and objective evidence of evolution.
Molecular data allows scientists to quantify the exact number of genetic differences between species.
While structures can be subject to convergent evolution, DNA sequences track lineage more accurately.
The more similar the nucleotide sequences, the more recently the species shared a common ancestor.
This molecular “clock” is more precise than comparing physical traits or embryos.
Therefore, biochemical evidence is considered the “gold standard” for determining evolutionary relationships.