• Core Assumptions of Analysis of Variance (ANOVA):

• Normality: Errors (and observation populations) are normally distributed.
• Homoscedasticity: Variances across treatment populations are equal (homogeneity of variances).
• Independence: Experimental errors and observations are independent of each other.
• Additivity: Treatment and environmental/block effects are additive.
  • Why "Blocks" is NOT an Assumption: Blocking is a technique of local control in experimental design (e.g., in RCBD) used to partition field heterogeneity, not an underlying statistical assumption of the ANOVA mathematical model.

• Assertion (A) is True: Two-dimensional difference gel electrophoresis (2D-DIGE) enables direct quantitative comparison of protein abundance across multiple experimental samples within a single 2D polyacrylamide gel.
• Reason (R) is True & Explains (A): Distinct protein samples are pre-labeled with charge- and mass-matched, spectrally distinct fluorescent dyes (Cy2, Cy3, Cy5) and pooled before isoelectric focusing and SDS-PAGE, completely eliminating gel-to-gel experimental variation.
• Conclusion: Both (A) and (R) are true and (R) is the correct explanation of (A).

Correct option: (1) Both (A) and (R) are true and (R) is the correct explanation of (A)

• Statement (I) is True: In MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization Time-of-Flight), analyte molecules co-crystallized with an organic matrix are irradiated by UV laser pulses, generating intact, gas-phase singly protonated pseudomolecular ions ($[M+H]^+$).
• Statement (II) is True: MALDI is a premier "soft" ionization method capable of volatilizing and ionizing very large, labile biological macromolecules (proteins $\gt 100\text{ kDa}$, intact polysaccharides) with exceptional picomole-to-femtomole sensitivity and minimal in-source fragmentation.
• Conclusion: Both Statement (I) and Statement (II) are true.

Correct option: (1) Both Statement (I) and Statement (II) are true.

• Selected Ion Monitoring (SIM): A targeted mass spectrometry acquisition mode in LC-MS and GC-MS.
• Operational Principle: Rather than scanning across a wide mass-to-charge ($m/z$) spectrum, the mass analyzer is set to transmit only specific predetermined $m/z$ values corresponding to the target analyte ions, increasing dwell time and improving signal-to-noise ratio by up to 100- to 1000-fold.

Correct option: (3) Selected ion monitoring