Author: Nishchal Soni

Answer: C. The smoothness and fluidity of handwriting

Explanation: Line quality assesses how steady and consistent pen strokes are; shaky or uneven lines may indicate forgery or disguised writing.

Answer: B. To test instrument response using known standards

Explanation: Calibration verification checks that the instrument accurately measures reference standards, ensuring the validity of subsequent sample analyses.

Answer: B. Diameter of the barrel’s bore

Explanation: Caliber refers to the internal diameter of a firearm barrel or the diameter of the projectile it is designed to fire.

Answer: C. It reveals stable isotope ratios like C13/C12

Explanation: IRMS analyzes natural isotope ratios, helping to trace geographic origin and detect adulteration in food products based on isotope signatures.

Answer: D. Contact muzzle imprint

Explanation: A contact gunshot produces a muzzle imprint or scorching on the skin, distinguishing it from distant or intermediate shots.

Answer: B. Lowest concentration quantifiable with acceptable precision and accuracy

Explanation: LOQ defines the minimum analyte concentration that can be reliably measured using validated analytical methods.

Answer: A. Femoral length

Explanation: Femoral (thigh bone) length is strongly and consistently correlated with overall body height, making it ideal for stature estimation.

Answer: B. Ion mobility spectrometry (IMS)

Explanation: IMS is a rapid, sensitive screening method commonly used at security checkpoints to detect trace levels of explosive compounds.

Answer: B. Lip prints

Explanation: Cheiloscopy is the analysis of lip groove patterns, which are unique to individuals and used in identification.

Answer: B. A profile that excludes individuals who cannot be contributors

Explanation: An exclusion occurs when an individual’s DNA allele(s) cannot be found in the evidence sample, signifying they are not a source contributor.

Answer: C. It separates fluorescently labeled DNA fragments by size

Explanation: Capillary electrophoresis enables high-resolution separation of STR alleles, where DNA fragments tagged with fluorescent dyes are sorted based on size and detected accurately.

Answer: C. Signature dynamics using biometric tools

Explanation: Biometric signature analysis records pressure, speed, rhythm, and stroke patterns, providing a dynamic comparison that can expose skilled forgeries.

Answer: C. Diptera (blow flies)

Explanation: Blow flies are typically the first colonizers of a corpse. Their life cycle stages (egg, larvae, pupae) help estimate time since death in early postmortem intervals.

Answer: C. Atomic emission spectroscopy from plasma

Explanation: LIBS uses a laser to generate a microplasma on the sample surface, and the emitted light is analyzed to determine elemental composition—a rapid tool in trace evidence analysis.

Answer: C. Forensic limnology – Study of diatoms in drowning cases

Explanation: Forensic limnology involves examining aquatic ecosystems; identifying diatoms in bone marrow supports a diagnosis of antemortem drowning.

Answer: D. Spectral envelope (formants)

Explanation: Formants are resonant frequencies shaped by vocal tract anatomy and are highly individual, making them crucial in speaker identification.

Answer: C. The scientific validity and reliability of the method used

Explanation: The Daubert standard evaluates whether expert testimony is based on scientifically valid reasoning and methodology that can be tested and peer-reviewed.

Answer: B. Internal standard response suppression

Explanation: Matrix effects can cause ion suppression or enhancement. Comparing internal standard signal in matrix vs. neat solution reveals this impact.

Answer: D. IBIS

Explanation: IBIS (Integrated Ballistics Identification System) allows forensic labs to compare bullet and cartridge case markings to link firearms to crimes.

Answer: C. It originates from epithelial cells via casual contact

Explanation: Touch DNA comes from skin cells deposited on objects after minimal contact, and can be recovered using swabbing and amplified for STR profiling.

Answer: C. Visualizing fingerprint residues on non-porous surfaces

Explanation: Powder dusting is commonly used to detect and develop latent fingerprints left on smooth, non-porous surfaces like glass, plastic, and metal.

Answer: B. Pelvis morphology

Explanation: The pelvic bone exhibits the most sexually dimorphic characteristics, including the subpubic angle, greater sciatic notch, and shape of the pelvic inlet.

Answer: C. Polarized light microscopy (PLM)

Explanation: PLM is optimal for identifying birefringent properties of synthetic and natural fibers, which helps in classifying textile evidence by type and origin.

Answer: C. Image file size unusually large

Explanation: Steganography hides data within other files, often increasing file size disproportionately. Analyzing such anomalies helps detect hidden data in forensic digital investigations.

Answer: B. Detection of lead, barium, and antimony via SEM-EDX

Explanation: Confirmatory analysis of GSR is performed using Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy to identify characteristic particles from primer residues.

Answer: C. Detection of D-dimers

Explanation: D-dimer presence indicates fibrinolysis, which occurs in menstrual blood but not in peripheral blood. This helps distinguish between the two in forensic cases.

Answer: C. It supports the inference that every contact leaves a trace

Explanation: Locard’s Principle is foundational to forensic science, emphasizing that perpetrators of a crime will bring something into and leave something from the crime scene.

Answer: C. Legal insanity and criminal responsibility

Explanation: The M’Naghten Rule assesses whether a defendant understood the nature of the act or knew it was wrong at the time of the offense.

Answer: C. Complementary binding of labeled probes to target sequences

Explanation: Hybridization involves single-stranded DNA probes binding to their complementary sequences on denatured DNA, enabling detection and identification of specific loci.

Answer: C. Presence of pour patterns and ignitable liquid residues

Explanation: Pour patterns and positive chemical tests for accelerants (e.g., via GC-MS) strongly suggest deliberate ignition using ignitable liquids.

Answer: B. DNA barcoding of mitochondrial COI gene

Explanation: The mitochondrial cytochrome oxidase I (COI) gene is highly conserved within species and varies between species, making it ideal for forensic identification of animals.

Answer: D. Gas chromatography-mass spectrometry (GC-MS)

Explanation: GC-MS combines the separation capabilities of gas chromatography with the identification power of mass spectrometry, making it the gold standard in confirmatory toxicological tests.

Answer: B. Collecting and labeling evidence with timestamps and signatures

Explanation: The chain of custody ensures traceable documentation from the scene to court. Accurate labeling and logging are critical to maintaining evidentiary integrity.

Answer: C. GRIM (Glass Refractive Index Measurement)

Explanation: GRIM is a precise method that heats immersion oil with glass fragments to determine the exact match of refractive index, which is highly specific in glass comparisons.

Answer: C. Antimony

Explanation: Antimony, along with lead and barium, is a characteristic element found in primer mixtures. These are detected using SEM-EDX for gunshot residue confirmation.

Answer: B. Video spectral comparator (VSC)

Explanation: VSC helps distinguish inks based on their light absorption and fluorescence characteristics and can determine the sequence of intersecting strokes in questioned documents.

Answer: C. It allows phenolphthalein to turn pink in the presence of blood

Explanation: In the alkaline environment of the test, hemoglobin catalyzes the oxidation of phenolphthalin to phenolphthalein, producing a pink color when blood is present.

Answer: B. Plastic polymers

Explanation: Pyrolysis GC breaks down complex polymers into smaller fragments, which are then analyzed for identification. It is especially useful for comparing unknown plastic materials.

Answer: B. Clavicle

Explanation: The clavicle is one of the last bones to ossify, with its medial epiphysis closing around age 25. It provides a reliable indicator of age in late adolescence to early adulthood.

Answer: C. Diptera

Explanation: Flies, particularly blowflies (family Calliphoridae), are among the first to colonize a decomposing body. Their developmental stages assist in estimating postmortem intervals.

Answer: C. SNP (Single Nucleotide Polymorphism) typing

Explanation: SNPs require shorter DNA fragments for amplification compared to VNTRs or STRs, making them particularly useful in degraded forensic samples.

Answer: B. ICP-MS

Explanation: Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is highly sensitive and ideal for trace elemental analysis in gunshot residue investigation.

Answer: D. DNA methylation pattern analysis

Explanation: Age-related DNA methylation changes in dental tissues can be quantitatively assessed, offering accurate biological age estimation in forensic contexts.

Answer: B. Fiber types and dyes

Explanation: Raman spectroscopy provides detailed vibrational information about the molecular composition of fibers and dyes, enabling nondestructive forensic comparisons.

Answer: C. Infiltration of neutrophils

Explanation: Neutrophilic infiltration indicates a vital reaction, which only occurs when circulation and immune responses are active, confirming the injury happened before death.

Answer: C. Denatures nucleic acids for hybridization

Explanation: Formamide destabilizes hydrogen bonds in DNA and RNA, facilitating strand separation crucial for downstream hybridization-based analyses.

Answer: B. Carbon monoxide poisoning

Explanation: Carboxyhemoglobin imparts a bright pink or cherry-red color to the hypostasis, which is a classic postmortem sign in CO poisoning cases.

Answer: B. Ion mobility spectrometry (IMS)

Explanation: IMS is portable, highly sensitive, and widely used for on-site detection of explosives and trace analytes on hands, clothing, or luggage.

Answer: D. Reaction Time-Based Implicit Association Test (IAT)

Explanation: IAT evaluates automatic associations and response times, with the assumption that lying increases cognitive load and delays reaction time.

Answer: B. Newton’s Second Law

Explanation: Newton’s Second Law (F = ma) helps in modeling bullet motion under gravity and air resistance for precise trajectory reconstruction in shooting incident analysis.

Answer: B. Mastoid process size

Explanation: The mastoid process is typically larger and more pronounced in males. It serves as one of the most sexually dimorphic features in cranial assessment.

Answer: B. Acid phosphatase test

Explanation: The acid phosphatase enzyme is found in high concentration in semen, helping distinguish it from other bodily fluids like saliva or sweat.

Answer: C. Pen lifts

Explanation: Pen lifts and connecting strokes are often subconscious and difficult to imitate or alter, making them reliable features in handwriting comparison.

Answer: C. 6-Monoacetylmorphine (6-MAM)

Explanation: 6-MAM is a unique intermediate metabolite of heroin and is not found in users of other opiates, making it a definitive marker of heroin ingestion.

Answer: C. Multiple contributors

Explanation: More than two alleles at a single locus suggest the DNA sample originates from more than one person, necessitating mixture interpretation strategies.

Answer: D. Impact spatter

Explanation: Repeated blunt force blows cause blood to radiate outward in a radial pattern, producing fine impact spatters around the point of contact.

Answer: C. Space between the end of a file and end of a cluster

Explanation: Slack space can contain remnants of previously deleted files or fragments, which may be valuable in digital evidence recovery.

Answer: C. They help identify the firearm used by matching markings on the cartridge case

Explanation: Breechface marks are impressed onto the primer or base of a cartridge case when the firearm is fired and can be compared microscopically for firearm identification.

Answer: C. Femur

Explanation: The femur, being the longest and strongest bone in the human body, has a well-established correlation with overall height, making it ideal for stature estimation.

Answer: C. Teichmann test

Explanation: The Teichmann test is a confirmatory microcrystal test for blood, not a presumptive one. Presumptive tests suggest presence, while confirmatory tests prove it.

Answer: A. Charred wood

Explanation: Porous and absorbent materials like charred wood can trap and retain ignitable liquid residues, making them valuable in fire debris analysis using GC-MS.

Answer: B. Bullet casing

Explanation: Touch DNA evidence, such as skin cells from handling, is often present in trace amounts on objects like bullet casings, making them highly prone to contamination if not properly handled.

Answer: C. Ambient temperature

Explanation: The rate of insect development is temperature-dependent; higher temperatures accelerate larval development, making temperature a critical factor for postmortem interval estimation.

Answer: C. Raman Spectroscopy

Explanation: Raman spectroscopy is non-destructive, highly specific, and suitable for detecting organic and inorganic components of aged ink without sample extraction.

Answer: B. Contact shot over bone

Explanation: Stellate tearing is caused by gases expanding beneath the skin during a close-contact gunshot, especially over hard surfaces like skulls, producing star-shaped lacerations.

Answer: B. Amelogenin gene

Explanation: The amelogenin gene has length polymorphisms on the X and Y chromosomes, making it a reliable marker for determining biological sex in forensic DNA analysis.

Answer: C. Polarized light microscopy of fibers

Explanation: The McCrone method involves detailed examination of micro-evidence, such as synthetic or natural fibers, using polarized light microscopy for identification and comparison.

Answer: B. Age estimation in adults using tooth wear

Explanation: The Gustafson method relies on physiological changes such as secondary dentin deposition, root resorption, and attrition to estimate age in adult teeth.

Answer: C. Precipitin test

Explanation: The precipitin test detects species-specific antigens using antisera and is effective in determining whether a sample is human or animal in origin.

Answer: B. Autopsy (Sleuth Kit)

Explanation: Autopsy is a GUI-based tool built on the Sleuth Kit framework, widely used for recovering and analyzing deleted files and disk structures during digital investigations.

Answer: C. Burn test with odor observation

Explanation: The burn test helps differentiate fibers based on their burning behavior and odor—natural fibers like cotton smell like burning paper, while synthetics may melt and emit chemical odors.

Answer: B. Pubic symphysis morphology

Explanation: The pelvis, particularly the pubic symphysis, offers the most reliable morphological indicators for determining sex due to pronounced differences between male and female anatomy.

Answer: C. It allows for exact mass measurement of unknowns

Explanation: LC-QTOF-MS (Quadrupole Time-of-Flight) allows for high-resolution, accurate mass detection, ideal for identifying unknown or emerging toxicants without pre-selection.

Answer: C. High polymorphism and individualization potential

Explanation: A large number of rare alleles increases the power of discrimination at an STR locus, enhancing its utility for individual identification in forensic DNA profiling.

Answer: A. Principle of exchange

Explanation: Locard’s Exchange Principle states that contact between two surfaces will result in a mutual transfer of trace evidence, such as partial footprints or fibers.

Answer: B. CT scan

Explanation: CT scanning provides high-resolution, 3D visualization of internal structures and is highly effective in detecting and localizing metallic foreign objects in bones.

Answer: C. To validate data integrity

Explanation: Hash values (e.g., MD5, SHA-256) are used to ensure that the data acquired during forensic imaging remains unchanged throughout analysis and is admissible in court.

Answer: D. Dispersion

Explanation: Dispersion affects how glass interacts with light across different wavelengths, influencing its refractive index. Matching dispersion curves can help differentiate similar glass types.

Answer: C. To quantify trace elements with high sensitivity

Explanation: Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is capable of detecting ultra-trace levels of metals and other elements, making it ideal for forensic soil, glass, and toxicological analysis.

Answer: C. Diluted sample

Explanation: A highly diluted bloodstain may contain insufficient hemoglobin to produce a detectable color change in presumptive tests like Kastle-Meyer, resulting in false negatives.

Answer: B. Infrared reflectography

Explanation: Infrared reflectography allows for differentiation of ink types based on their absorption and reflectance in the IR region, making it useful for detecting alterations or obliterations in documents.

Answer: C. Gas Chromatography-Mass Spectrometry (GC-MS)

Explanation: GC-MS provides both separation and structural identification of compounds, making it the gold standard confirmatory test for controlled substances like cocaine.

Answer: C. Drowning

Explanation: Frothy fluid in the lungs and airways is a classical sign of drowning due to the mixing of water and surfactant in the lungs, forming stable foam.

Answer: B. A speaker’s unique and individual language use

Explanation: An idiolect is the personal language style of an individual, encompassing vocabulary, syntax, and grammar patterns, which can assist in author identification in forensic cases.

Answer: C. Criminal responsibility based on insanity

Explanation: The M’Naghten rule evaluates whether a defendant understood the nature or wrongfulness of their actions due to mental illness, forming a legal standard for insanity.

Answer: C. Moist, anaerobic, and sealed environments

Explanation: Adipocere forms through hydrolysis of fat tissues in moist, oxygen-poor environments, commonly seen in submerged or buried bodies.

Answer: C. Small particle reagent (SPR)

Explanation: SPR is used on wet, non-porous surfaces and adheres to the fatty components of fingerprint residue, making it ideal for submerged items.

Answer: C. Linking cartridge to a specific firearm

Explanation: Toolmarks left by a firing pin are unique and can be matched to a firearm’s breech face and firing mechanism using comparison microscopy.

Answer: C. Femur

Explanation: The femur is the longest bone in the human body and has well-established regression formulas for estimating stature in forensic analysis.

Answer: B. Allele dropout in low-template DNA

Explanation: Stochastic effects refer to random variations during PCR amplification, often leading to allele dropout or imbalance in low-template DNA samples.

Answer: B. Electrostatic detection apparatus (ESDA)

Explanation: ESDA is used to detect indented writing and pressure patterns on documents, which can reveal underlying impressions even after the original text is removed.

Answer: D. Projected spurts with pulsatile flow

Explanation: Arterial spurting results in a projected pattern with a pulsatile appearance due to the pressure of the heartbeat pushing blood from a breached artery.

Answer: C. Shed hair shafts without roots

Explanation: Mitochondrial DNA (mtDNA) is useful when nuclear DNA is degraded or absent, such as in hair shafts, bones, and teeth, where nuclear DNA may not be present.

Answer: C. Stabilize the bullet in flight via spin

Explanation: Rifling imparts a spin to the bullet, increasing its stability and accuracy. The lands and grooves also leave unique markings for forensic comparison.

Answer: C. Acid phosphatase

Explanation: Acid phosphatase is present at high levels in seminal fluid and serves as a reliable marker in presumptive tests for semen.

Answer: C. Blowfly maggots (larvae)

Explanation: Blowfly larvae colonize a body quickly after death. Their development stages can be used to estimate the PMI during the early phases of decomposition.

Answer: B. Thin-layer chromatography (TLC)

Explanation: TLC is widely used to separate ink components, helping distinguish visually similar inks based on their chemical makeup and mobility on the TLC plate.

Answer: A. Leuco crystal violet (LCV)

Explanation: LCV reacts with the heme in blood to produce a violet-colored product, making it useful for visualizing bloody impressions like footprints or fingerprints on porous surfaces.

Answer: B. Likelihood ratio

Explanation: The likelihood ratio compares the probability of observing the DNA evidence under two competing hypotheses, aiding in the statistical interpretation of forensic DNA matches.

Answer: C. Detecting tampering or image editing

Explanation: JPEG quantization table analysis can reveal inconsistencies in compression artifacts, suggesting splicing or manipulation in a digital image.